I think the "easier to understand" part of 6.0 is really the lack of understanding needed to judge the winner. Frankly, there were plenty of disagreements about judging and "fix" was bantered then and now. The audience judged the skaters based on how they looked, how hard they thought the skater worked and how much they liked the skater/country/etc. In many cases, their preferences matched the judges, although 2002 comes to mind...
IJS is more like the old ISI competition scoring: there are required elements, each one gets a grade, toss some artsy-fartsy points in the pot and tada! You have a less-subjective method of choosing a winner, with numbers that quantify the outcome. Unfortunately, the math is complicated under IJS. The audience has to be educated, but the casual fan doesn't want to be schooled. Maybe the "Boys Who Score" can figure out a simple way to explain why two falls and a few underrotated jumps can't offset huge PCS scores. *whistles in the dark* A scary thought, indeed.
I believe that Americans lost interest when skating became an Job for the entire family. Families mortgaged their houses, took second or third jobs, split up their families and relocated to pursue training. Wardrobe alone was enough to turn many people's stomachs, which is one of the reasons parents shy away from letting their kids start taking lessons today. They know it's an expensive sport, most coaches are very honest about it, so those without disposable income stay away. Skating parents think they're being funny when they warn off newbies with a "get out while you can" comment, but they are being honest and perhaps, regretful in some ways.
Can I also say that skating has overwhelmed its intended audience with the level of skating we see today, with perfectly choreographed programs done by boneless spinners and wicked jumpers? Only the naive can watch a senior competitor skate and think "I can do that." Back in the 1960's, crazy people could and would "go for it" and achieve some level of success on par with the elites.
Plus, there are plenty of other, seemingly less-expensive options to figure skating in the US. Kids are overscheduled with activities and interests. People my age make remarks like "we used to play outside all afternoon until dinner - why don't kids today do that?" My 10-year younger relatives remark on "instead of the mall, we hung out at the ice rink or the pool." (Today, that would involve explanations to child protective services.) The rinks that are really "making it" have afterschool programs and weekend skating. They have very little public skating because they make more money with organized hockey. Parents love organized hockey - you can drop the kid off and go shopping at Walmart. When I skated, FS clubs rented ice and conducted the classes. Today, we have rinks hiring professional instructors to teach toddlers how to (kudos to slusher) "lick the ice." Rinks run drop-in freestyle sessions and everyone's schedules are so busy and erratic that families can't commit to a Club-contract ice package. Some clubs still have their ice time, but fewer and fewer are able to offer that, which is why clubs are in decline as well. There's limited cameraderie in a sport like this, which is why the Team Trophy has been added to the Olympics.
I don't think the abolishment of Figures or the introduction of IJS has had as much impact on interest in skating as chalking it up to simple lifestyle changes.