To be fair, the greenfield advantage of a complete rewrite was also overestimated and frequently just lead to ungodly amounts of wasted resources on systems that never shipped or ended up being overly complicated. See https://en.wikipedia.org/wiki/Second-system_effect

AI lowered the cost of rewriting which means that more shitty systems ship because the rewriters don't run out of money before the rewrite is canceled. But it doesn't the solve the underlying problem of the people in charge of rewriting not understanding what features in the old system were actually important and which had to go.