Since you wrote the above I have had weekly lessons with a figure skating coach and I now have good edge control. Regarding your first statement, I get a lot of feedback from my skates, I can feel the edges very clearly, and for example I know if my forwards/backwards crossovers are wrong because the edges feel wrong. I adjust my technique until the edges feel right. Similarly, if I’m doing a forwards power pull, it’s all about the edge, to minimise the friction and ride the edge. People at public skating tell me that my ankles move about a lot in the skates, I’ve had people ask if my skates are special because of this. I wear Bauer 2S Pro custom skates, and they don’t restrict my ankles at all despite having a stiff shell. Years of basic drills have corrected my (bad) posture, and improved the basic stride and technique, to gain good edge control.
After three years of teaching myself, my skating was awful, bad posture, bad technique. I doubt it would have improved much after another three years, I would probably have continued fighting against awful technique and made small gains, limited by the fact that the basics were dreadful. I practiced regularly but all that did was reinforce bad practices. I don’t know if skating with laces undone would have helped someone so utterly inept as me.
As an aside, I’ve met quite a few adults who from the first session were learning phenomenally fast eg doing crossovers and spread eagle (mohawk) on the second session. They learnt at least ten times faster than most of us. In every single case the person was an athlete: a professional dancer, a tennis coach, a skier, a boxer, a black belt in a martial art etc. My belief is that thanks to regular exercise they have strength and flexibility, and thanks to years of training in their chosen discipline they have learnt how to control their body, and they have learnt how to learn new tricks. I assume that is a stage we all pass through when first learning to do a physical discipline.