Or they (Firefox folks) learned what happens when you (Netscape) try a major greenfield rewrite (Netscape v5) so ambitious that it becomes the example of why one should never rewrite.
And instead just back ported the lessons learned to make Firefox/Gecko better years earlier than a rewrite could.
That's why Servo exists in the first place. That's exactly the reason why always has been intended as a research engine, with an explicit focus on high modularity, and easy portability of single components, several of which were then incorporated into Firefox.
Especially the latter wasn't some kind of salvage, trying to squeeze value out of some theoretical project. It was an explicit goal from the beginning.
Facts don't matter, this is one of those QAnon things were people collectively fan-fiction an apocalyptic battle for them to be on the right side of based on nothing more than a vague dislike of women and minorities.
And it really doesn’t matter whst conventional wisdom holds, when the architecture of a project is based on flawed assumptions, or things just changed since it was architected.
And instead just back ported the lessons learned to make Firefox/Gecko better years earlier than a rewrite could.