Sure, "you" - as a reader of hacker news - can use Firefox (or a chromium fork). The problem is that most normal users have no idea about any of this stuff, and no understanding of why they might want to switch.
Realistically most people just don't care the same amount that the subset of privacy-obsessed+techies do.
How many people who use Chrome can or will even know to do so? Tech oriented people already have alternatives.