It really depends on your gut feeling about how deep the rabbit holes in terms of number of game changer vulnerabilities.

How many RCEs are in PHP of this kind? Many people would've said zero before. After the fixes, it may be zero again. It could be thousands, it could be eighty-six, it could be four, it could be zero. But even if you don't think it's zero again, most people will find themselves that there's probably not many left.

Extend this to other world ecosystem - how many high impact devastating security bugs are there? Dozens, hundreds, thousands, millions? At least when it comes to open source security, there has to be some low upper bound given how countable the number of projects there are where impact could be high and most have taken some care for their quality (despite obvious hardships). And while closed source software is harder to reason about (also on the ecosystem level), if there's a low upper bound for open source software surely the bound for closed source software can't be many orders of magnitude higher.

We now have new tools that allows us to discover these. Both the discovery as well as changes in the development process most are taken should bring these numbers closer to zero again. The main question is - are we working through a small backlog of issues, or a very deep one with no practical end? I'm still inclined to believe it's a manageable backlog, but I'm an optimist and everybody's intuitions differ on this.