Gmail is a significant enough profit center that it's unlikely to ever be under threat. Reader didn't directly contribute to the bottom line (and arguably led to fewer ad views).
It is a lot easier for people to protest by not doing anything than actually putting effort into it. Switching from Gmail to some other provider involves a lot of friction. Not using a newly released product (assuming this will be one) is fairly easy.
Such things are hard to judge. I have a feeling that a lot of people (a lot more than usual anyway) have recently transferred their email from an @gmail.com address to a Google hosted custom domain.