Rendering engine diversity is a different problem. In order to actually have a web standard, then we need at least two frequently-used implementations. If there is only one implementation, or one dominant implementation, then people stop coding to the spec and start coding to whatever works in browser.[0]
Right now, if Mozilla goes bust, then the last hope for web standards is the fact that Apple's mobile OS rules preclude shipping Blink on iOS. If everything is Chrome, then we're right back to the days of Adobe Flash Player, where bugs in one implementation effectively become part of the spec.
If we didn't have or didn't care about this problem, then yes - we could just clip FLoC out of the browser and run that. However, that also assumes Google won't mandate FLoC or ban alternative browsers. Their recent attempts to cut down on credential stuffing through headless CEF browsers[1] have already made it harder to actually ship an alternative browser that can log into Google. So hypothetical future Evil Google could totally say "no FLoC, no service" and we would be screwed.
[0] This is the same reason why WebSQL died on the vine. SQL is a standard with a lot of wiggle room, enough that most applications either only work on one particular flavor of DB, or ship separate drivers for each DB they need to work with. In practice everyone shipped SQLite, so WebSQL was just "here's a sandboxed SQLite instance".
[1] Which, BTW, is not a bad thing in and of itself.
Right now, if Mozilla goes bust, then the last hope for web standards is the fact that Apple's mobile OS rules preclude shipping Blink on iOS. If everything is Chrome, then we're right back to the days of Adobe Flash Player, where bugs in one implementation effectively become part of the spec.
If we didn't have or didn't care about this problem, then yes - we could just clip FLoC out of the browser and run that. However, that also assumes Google won't mandate FLoC or ban alternative browsers. Their recent attempts to cut down on credential stuffing through headless CEF browsers[1] have already made it harder to actually ship an alternative browser that can log into Google. So hypothetical future Evil Google could totally say "no FLoC, no service" and we would be screwed.
[0] This is the same reason why WebSQL died on the vine. SQL is a standard with a lot of wiggle room, enough that most applications either only work on one particular flavor of DB, or ship separate drivers for each DB they need to work with. In practice everyone shipped SQLite, so WebSQL was just "here's a sandboxed SQLite instance".
[1] Which, BTW, is not a bad thing in and of itself.