If you had asked me this 3 years ago I'd have said this is true. But today imho it's all opinionated bs, just like my comments following.
Let me put this out there - IT'S NOT THE SKATE. It's you and your bio mechanics. It's as simple as this even though bio mechanics in skates is a complex issue. If your bio mechanics are correct you can skate in anything - even clods with a frame bolted to them. Stiffness, heel lock, volume, length, forefoot width, profile, hollow etc are all secondary, you don't need this to be anywhere near perfect to skate well. What you need is good body alignment over the skate blade. Yes, stiffer skates will generally help you to skate a little better but they will not TEACH you to skate better.
If you want to skate better fix your bio mechanics first, make sure the holder is aligned central to your foot / ankle / knee / hip alignment. Then shim for ankle / knee / hip deviation. This is the quick fix but it comes with some issues, especially for beginning skaters and how their body adapts to skating over time.
Or learn to skate with your laces undone, stop using the boot as a crutch / excuse and teach yourself how to balance over the blade. Even holder alignment becomes less important. Add in strength work for legs and core and then you wont care what skate you are in as long as it is comfortable on your foot. Age, sex, size, weight, skating experience and equipment are irrelevant, anyone can learn to do this. Downside is you have to put in the time and effort and it is a long term development, upside is that over time you create the base to become the best skater you can possibly be.