It seems your premise is wrong since Firefox's market share has been steadily declining for years. Privacy apparently doesn't matter to that many people.
I suppose you're right, I just know that privacy has become more of a known issue than it was 10 years ago. I guess users don't back that knowledge up with action by switching browsers.
I'm sure losing the only advantage over technically superior Chrome is going to help their market share!
Losing a major technical disadvantage will probably help.