- skill is generally log-normally distributed, so there's few exceptional people anyway (see also: sturgeon's law, 99% of everything is crap)
- smaller/earlier fields may self-select for extreme talent as the support infrastructure just isn't there for most to make it, leading to an unrealistically high density of top talent
- it's a fundamentally different thing to make a substantial impact than to cookie-cutter a todo list app by wrangling the latest 47 frameworks. in that, it's highly unlikely that the typical engineering career trajectory will somehow hit an inflection point and change gears
- presumably, from a cost/benefit perspective there's a strong local maxima in spewing out tons of code cheaply for some gain, vs a much more substantial investment in big things that are harder to realize gains (further out, less likely, etc). the more the field develops, the lower the skill floor gets to hit that local maxima. which therefore increases the gap between the typical talent and the top talent
- there's not a lot of focus on training top talent. it's not really a direct priority of most organizations/institutions by volume. most coders are neither aiming for or pushed towards that goal
All told, I think there's a bunch of systemic effects at play. It seems unlikely to expect the density of talent to just get better for no reason, and it's easier to explain why left unchecked the average talent would degrade as a field grows. Perhaps that's not even an issue and we don't need 'so many cooks in the kitchen', if the top X% can push the foundations enough for everyone else to make apps with. But the general distribution should be worth paying attention to bc if we get it wrong it's probably costly to fix