I suspect the era of VC-money and ZIRP led to a large number of engineers who were disconnected from successful long-term business outcomes, so there was no incentive to simplify.
VC-money and ZIRP is a convenient shorthand for what's changed, neither are terms I think particularly encapsulate what did change, but I think it's very hard to argue that it's still just as easy to get a bunch of funding without a business model. (aside from in AI perhaps?)
It's entirely possible to measure teams on business outcomes without having them own things end-to-end, but to be really effective in this they'll need to collaborate with the other teams across the company - which is generally a desirable outcome.
In my experience, this exists in a few, rare (investment bank) trading floor technology teams. From a distance, it looks like traders who are programmers.