The industry grew a lot. I don't have the recent numbers but around the time AWS became a household name the growth in the industry was about 5% yearly. Programming was one of the fastest growing industries for a while (probably not true with recent wave of layoffs, but it's probably still growing). But it grows very non-uniformly. There's a lot more growth in the Web sector. Web is one of the areas with more simplified infra, which can be catered for by the public cloud providers more easily. So, while there's growing demand it's satisfied by services rather than employees knowledge.
Another factor is promotion into management. Programmers have very little to look for in terms of professional growth. Those who "make a career" tend to go into management. It's so to the point that if you were in the industry for 20 years and you aren't a head of a department at least, you are seen as a loser. So, a lot of those who did know their trade decade or two ago are ticking boxes in Excel today.
Yet another aspect is the nature of venture capital investment into startups which encourages very wasteful short-term solutions. So, while it may be a more financially sound strategy to do things on-prem, the investments are rationed in such a way that there's no money to build the infrastructure upfront, even if in the long run this would've been a better financial strategy.
Another factor is promotion into management. Programmers have very little to look for in terms of professional growth. Those who "make a career" tend to go into management. It's so to the point that if you were in the industry for 20 years and you aren't a head of a department at least, you are seen as a loser. So, a lot of those who did know their trade decade or two ago are ticking boxes in Excel today.
Yet another aspect is the nature of venture capital investment into startups which encourages very wasteful short-term solutions. So, while it may be a more financially sound strategy to do things on-prem, the investments are rationed in such a way that there's no money to build the infrastructure upfront, even if in the long run this would've been a better financial strategy.