No, indeed it is not. If the problem is that people are getting phished because they type their info into a spoofed login page, how would making one standard login page be the answer?

Well, I for one don't want all of my accounts linked together. I don't think that's information that Facebook or Google needs.

Definitely! Lump all my logins into a single point of failure, so that if something is compromized, everything is!!! Awesome idea. :/

It's also a single point to defend.