I think the main reasons are to sabotage Firefox and to increase their partnerships with the other FAANGs.
https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...
Of course, monopolists and their toadies don’t acknowledge all of their dirty behavior.
But Google was a mostly reasonable partner to browser makers until they got into the business themselves. After Chrome shipped, Google properties started mysteriously becoming slower or broken in Firefox in ways that had no good technical support and that consistently siphoned large numbers of Firefox user over to Chrome before being addressed. It happened over and over on major Google properties like Gmail and Docs all through the 2010s. Jonath's Twitter thread is gone but the reporting isn't https://www.zdnet.com/article/former-mozilla-exec-google-has...
And they did it to IE and Edge too, until MS finally capitulated and jumped on Google's tech to escape the sabotaging. There's reporting on that too https://www.neowin.net/news/former-edge-intern-says-google-s...
Well, and Mozill gladly accepted the deal, being passive and without even trying to be self-sustainable. The (only) culprit here isn't Google. Mozilla's mismanagement has played a big role.
Run a team of 10 engineers for 20+ years on $1m? Wow that's a bargain!
(I assume you meant dies by 2006 :D)