They are not, and neither are you.
It may affect the adoption rate of your app if you don't include a "login with facebook" option, maybe. But that is a small price we all have to pay to influence change.
"My cog in the machine is not hurting anyone, why should I care" is how things get very, very bad.
making the hard choice is easy when you have nothing to lose, and it's even easier when you're so rich that the losses don't matter. the folks in the middle have just enough that it would really hurt to lose it. I can't say I blame them for guarding that jealously.