Okay, I am finally back and still wish my last try at this response wasn’t eaten by the internet gods…

How bad are the depressions?  It costs more to keep thick ice, so if they have to maintain a mostly thicker sheet to cope with the higher spots that isn’t good.  However, the concrete probably is one of the least costly parts of the rink to renovate.  I’m more worried they also have to replace the chiller, resurfacer, and other systems by now too.  This can happen.   A formerly “local” rink just did a massive renovation of all their systems, boards, and all this past year.  “My” rink is also in the midst of a renovation too.  The first is a tiny and seasonal town rink, empty for public until the free school kid thing they generously provide, but somehow they got the funding.  They even hosted a major women’s world hockey tournament this spring.  “Mine” is a county rink funded by the youth hockey program.  Those parents and coaches do so much to keep everything going.

Essentially it is vital to get a grassroots thing going for the support and funding.  Try to work with the hockey kid contingent, write to the papers, and get on Facebook about it.  Even my tiny (under 2,000 people) and very impoverished hometown has made funding and volunteering available for a winter outdoor rink recently thanks to grassroots involvement.
If the concrete base is the biggest problem I wouldn’t worry too much.  If they think pretty much everything needs to be upgraded then get to work on social media and such to save the rink.  It can be done.  I’m not kidding about the small town run place getting a total revamp all while charging 5 dollars for public and offering hours of free ice to the kids from the school next to it.  They replaced everything except the resurfacer (and might have, but I can’t say for sure.) 
My understanding is that Bowie is a larger population area by far, so getting local groups to rally for it could make a big difference.

Back to the issues…
I’m worried the structure itself could be problematic and more so the systems required of a rink, but that isn’t insurmountable.  The concrete is not much of a factor at all compared to what else is probably going on.  Showers, locker rooms, chiller, other systems, resurfacer,… those add up.  The floor is only an easy example. 

Shoot, I typed up a long thing, and the internet ate it.  (I have atrocious signal where I am.)

For now I’ll say that sucks, but hopefully they’ll invest in keeping it going.  (I had a bunch to say about it coming from what I know as a rink employee and as a skater, but I better go to sleep soon.)

Not so many as it appears. I'm pretty sure some of the rinks I've listed have disappeared since Covid, or were already gone. And many are seasonal, and are currently closed. Some stadiums are only ice rinks for special events, like professional hockey games.

Fort Dupont and Mount Vernon are closed for construction. Dr. John J. McMullen (Annapolis), said they had no public sessions, and that I could only enter freestyle sessions with a coach! (I'm not certain they meant that the coach had to be with me, but that was my impression.) I'm sure there are others.

I know a lovely lady who lives near Baltimore who skates south of the Beltway. In fact there are a lot of people who are driving hours. And area traffic jams are worsening. Prices went up, and pre-registration requirements often added, to handle Covid-19 health concerns. Covid is being dealt with better now, but concerns, prices and pre-registration remain.

And I included rinks well outside the DC metro area.

(A lot of the pro shops have closed or merged too.)

A lot of sports and recreational facilities closed with Covid, and never re-opened. Others took that time to start reconstruction: ice rinks have a finite lifetime, and some were built before people had learned to deal with frost heave and erosion problems under ice rinks by heating the underlying structure, or used structures that weren't strong enough.

Private ice rinks never were a particularly great business investment. Most sports and recreational facilities need government and/or private subsidy. It's difficult to re-establish those relationships in a short time period, and some sponsors are out of business or in economic trouble.

Global and regional warming don't help.

To what extent have the same things affected rinks outside the U.S.?

I maintain a bunch of web pages on a non-professional basis, and have let them go far out of date, including this list:

http://alltherinks.com which remaps to http://mgrunes.com/dcicerinks.html
and an overall map:
http://mgrunes.com/dcicerinksmap.html

I plan to update this list over the next year or so, by contacting each rink.

E.g., I recently found out that Tucker Road has re-opened, and that there are rinks in Leesburg & Springfield, VA.

If you know of any rinks that I left out, or that have permanently closed, or anything is wrong, please say so. I would love the rink name & city, a phone number or web page. Also whether you have verified it is open, or is expected to open, within the next year or two.

You don't have to give me complete info. But what I try to list is in the NOTES section:

Facility Name with website link
  Social media page with link
If needed: Note: I have not verified rink is open or will re-open.
If needed: Note: Rink is seasonal; also depends on weather.
If needed: Note: Rink is Seasonal: Open around Christmas
Address with map link
Phone: ?
If not on website: Session schedule (link and/or phone for public, freestyle, dance sessions)
Classes not on rink's website: (link and/or phone)
Non-hockey Club(s): ?

I don't list hockey clubs & sessions because most rinks list them on their own websites.
Many skating clubs offer their own skating sessions and classes, in addition to those offered by rink - I haven't listed those here -- see club's website. Many of these require that you belong to the club.

Thanks!

P.S. Many rinks don't keep their web pages up to date. Some have a social media page they keep more up to date, which I try to list. (Perhaps the web designer owns the site registration, and charges a lot of money to update it. Not unique to ice rinks - many organizations run into that. If they don't pay enough, some web designers let the web page address lapse, remap to a competitor or an inappropriate site.) So call ahead before visiting a rink you haven't recently visited! Also ask whether you must pre-register.

USFS doesn't want people attempting figure skating stuff in blades that aren't meant for figure skating. Flat = speed skater. Concave = unable to skate on edges, which is what figure skating depends on. Also, have you seen anyone try to skate with a concave? I have, in LTS. Never had their blades sharpened and were on a factory 'sharpening.' In other words, can't skate.

Blades with circular toe picks? That seems to me designed to cause faceplants. Toe picks are sharp for very specific reasons; namely, to assist with those jumps and spins.

As for blade technology, people are working on similar things. All that stuff you listed isn't illegal, but the technology is not there for wide implementation - or is downright impossible without making skates too heavy to wear. Related, check out Blade Science: https://www.blade.science

There are augmented reality programs out there. Some countries, I think Japan, uses those in their newscasts to calculate speed, jump distance, jump height, etc. It wouldn't surprise me if those kind of programs are being used in national-level training centers.