I'm going to have to disagree with you as well
My brother started taking photography seriously when he was living in Japan for a year. Within a year he went from being general capable (I can take a picture and that's it) to being fairly expert. Enough that he considered briefly making a living doing photography. He credits a lot of that rapid growth to getting instant feedback. Yes, people just taking pictures willy nilly and & looking at the results by itself does not make for fast skill building. But I would suggest that for someone who is interested in the craft, it is impossible to not see that immediate feedback -- even if you still need to fire the picture up in a power editor to be 100% sure -- versus taking pictures in a black hole and not seeing the results for hours at a minimum is an incredibly faster iterative cycle.
If the same people who grew up fascinated with cameras & photography thirty years ago had the digital cameras of today when they started out, there is no doubt at all that they would have become the experts they eventually became much, much, MUCH faster.
But obviously it has to be something a person cares about and invests the time to learn. Learning about composition, aperture, exposure & white balance are all important things, but they're things you can learn about a hell of a lot faster when you can do it in the field and see theory put into practice before your very eyes.