It's not just short attention span.
A lot of coaches look at Basic Skill classes as very preliminary training. Kids are taught one way of doing things, and even with that method, the coach doesn't worry too much about exactly what they do. Then, when they get to freestyle, they will learn very different ways of moving. I think it is so they can start jumping while they are young, before they have actually mastered basic strokes and edges.
For us adults, that seems inefficient. I like to learn how to do something RIGHT, one skill at a time, before moving on to the next thing.
Unfortunately, in the U.S. most coaches tend to teach all the standard ISI and especially the USFSA classes the kid way in that - even the adult classes. Part of the reason is the expectation of spending a very small number of minutes at a time on each skill in each lesson, because that's what the USFSA and PSA say to do. There is no real attention paid to proper technique in low level classes. Some of the special clinics, like some ice dance clinics, and perhaps some non-standard classes that focus on spins and jumps, that are designed by a good coach, are taught with more attention to proper technique. I found them more appropriate to me. But I guess it is a lot harder for a coach to design their own class, and a lot harder to get approval from the skating director to teach them. There may be some insurance issues too - BS registration includes sports liability insurance for the coach and perhaps the rink, provided the coach stays completely within the standard syllabus. And there are risks - the coach and rink can't guess how many people will sign up for a newly designed class.
I noticed some of the same type of issue in kayaking classes. E.g., American Canoe Association [ACA] classes teach very inefficient ways of doing moving, using a very standardized syllabus. Then, in later classes, techniques are revised, and will probably be revised again in private lessons. At all times, attention is paid to injury issues, and movement techniques, that are largely specific to hypermobile athletes - which I'm not. Efficient ways of moving are mostly reserved for elite level competitive athletes, and are generally not taught in ACA classes. Then I took some lessons from a coach who ignored ACA standards, and taught everybpmr the elite techniques from the start. He also developed his own disciplined technique and sequence of teaching people in groups, including individual feedback, that worked much better than the more casual group teaching techniques the ACA encouraged. He met a lot of criticism from other instructors, and from some others, but the ways he taught us to move, and his teaching methods, worked overwhelmingly better. (In fairness, I am not familiar with the modern ACA syllabus. Perhaps they have improved...)