Mozilla making choices specifically to try to "keep up" with Chrome has objectively failed: Firefox's marketshare has plunged so far that it's getting harder to keep using it on the web, as developers simply stop testing or caring much if it works with their site.
I think this is because simply chasing Chrome didn't have the desired effect anyway. By doing so, Mozilla hurt Firefox by gradually reducing what differentiated it from Chrome in the first place, relegating it to be kind of just a worse Chrome that looks even weirder.
A similar statement would be something like, "Firefox may as well pledge to support Web Environment Integrity; otherwise, people will just use Chrome."
In a totally different vertical, Valve has made interesting choices. To my knowledge, they do not provide a way to do attestation on Steam hardware devices, so games that want to support Steam hardware simply have to get rid of their intrusive DRM and anti-cheat, or at least significantly loosen it. Depending on how you look at it, this has either been a massive success or a massive failure. After all, a lot of big games don't run; Fortnite, Valorant, etc. But on the other hand, it remains a very powerful incentive for publishers and developers to reconsider their choices, as these devices still do have a non-trivial marketshare. (And for smaller games this obviously is hard to ignore, probably often moreso than intrusive DRM.)
Mozilla may have been ultimately correct that the choices they made helped them stay relevant; it's hard to know for sure how much their marketshare would be different today if they made bolder choices, but in the long run I think it has doomed them, as it is now unclear what even really differentiates Firefox. The last remaining thing seems to just be that you can run the full version of uBlock Origin, which is pretty valuable and all, but I'm not sure it makes up for the deficiencies. (I also like Container Tabs, but I think that feature is pretty niche, possibly somewhat by virtue of the fact that Firefox is now pretty niche.)
I'm currently using Librewolf. My long term hope was that Ladybird would become the browser that does what Firefox should have, but when I asked Andreas Kling whether or not Ladybird would try to support EME/Widevine in an HN thread, there was no reply, which is pretty close to "probably".
