Having flashbacks of “<!--[if IE 6]> <script src="fix-ie6.js"></script> <![endif]-->”
Not sure how you got from that to “Google is ignoring standards”.
Their board syphons the little money that is left out of their "foundation + corporation" combo, and they keep cutting people from Firefox dev team every year. Of course they don't want to maintain pieces of web standards if it means extra million for their board members.
I'm convinced Mozilla is purposefully engineered to be rudderless: C-suite draw down huge salaries, approve dumb, mission-orthgonal objectives, in order to keep Mozilla itself impotent in ever threatening Google.
Mozilla is Google's antitrust litigation sponge. But it's also kept dumb and obedient. Google would never want Mozilla to actually be a threat.
If Mozilla had ever wanted a healthy side business, it wasn't in Pocket, XR/VR, or AI. It would have been in building a DevEx platform around MDN and Rust. It would have synergized with their core web mission. Those people have since been let go.
That seems to fail occam's razor pretty hard, given the competing hypotheses for each of their decisions include "Mozilla staff think they're doing a smart thing but they're wrong" and "Mozilla staff are doing a smart thing, it's just not what you would have done".