But, what about the people who don't use Chrome? I would hope that most people who know what EFF is already don't. Firefox will surely come with a way to disable it, or you'll configure it to always send "my little pony" or something like this.
In the end, this seems to really be about Google (with a browser) competing against Facebook and other ad providers (who don't have a browser).
What's interesting is that since these "FLoC cohort" identifiers are generated by the browser itself, it's even easier than "disabling" it.
They just won't implement it in the first place.