[pluma]

The distinction between accidentally building software that performs badly in any browser other than your own and intentionally doing so to deliver a degraded performance to people not using your browser is very small and hard if not impossible to determine from outside.

There is no good case that Google intentionally built the software in such a way that it would be slow in Firefox. But e.g. by not testing the app in Firefox or by explicitly using Chrome-specific optimisations or having the Chrome team create specific optimisations for those web apps (i.e. "good cross-team communication") you can effectively accomplish the same without ever having to spell it out as an intentional strategy.

If you build a browser with a significant marketshare and you also build widely used web apps, not spending any resources on fixing cross-browser compatibility or performance issues is effectively anti-competitive. Deciding not to correct "happy accidents" like "forgetting to test your apps in other browsers" leading to a competitive advantage is as bad as intentionally doing the same from the get-go.

We're talking about an international megacorp that is worth more than half a trillion dollars at this point. There are no accidents, especially not many identical accidents that remain consistent over years.