It's not sbout monopolies, it's about survival of Google's core business model.

All other browsers whose businesses are based on selling ads, face the same risk. They're ALL between a rock and a hard place:

• On one side, the EU and other countries want to push privacy laws that protect their citizens from getting casually spied on by foreign entities
• On the other, Google's core business model relies on spying on users and reselling the use of that data to the highest bidder... many of them being foreign entities to the targetted people

If both Google/browsers/Ad sellers, and Ad purchasers, don't come up with something that is tracking, but cuacks like privacy, the whole Ad ecosystem is at risk.

FLoC is an attempt at compromise, by having an intermediary (the browser) who gathers full tracking data, but only sells a "reasonably anonymized" version.

Of course Ad purchasers see that as an inferior product, so they aren't keen to jump onto it... but if they all don't get something like that going on, then everyone's going to get shut down, with Google standing to lose the most.

From the end user's perspective, their failure would be slightly better, but otherwise worse than the current state of things:

1. Less tracking on sites that didn't rely on it in the first place
2. More paywalls on sites that lose Ad revenue
3. More sites asking people to enable full tracking in order to access their content

IMHO, stuff like FLoC would be a better solution.