[Scarbutt]

You are very optimistic, unless Mozilla gets really innovative, I don't see how Mozilla will survive in the long run, or at least be relevant enough to put pressure on competitors. I don't think your two reasons are good enough, most users don't care or know about the surveillance issues, and while servo maybe prove to be a technically superior browser, that's not enough.

[Manishearth]

Technically superior = faster/less bloat, and that could mean a lot.

People moved to firefox because IE was slow and sucky. They moved to Chrome because Firefox was bloated. Now some are even moving back to Firefox because Chrome guzzles RAM. Servo would be an ideal next step; a large architectural change like that is perfect for gaining lots of traction.

[fabrice_d]

Firefox beat IE on features like tab browsing and popup blocking, not really on speed. Servo should be better than gecko, but there's so much more to a browser than the runtime that it's hard to do a fair comparison yet.