There's a real lack of responsibility from a lot of players these days. The amount of times I see people leave the objectives unguarded is becoming more and more common, most notably on Hypergate. I'm happy to put in a defensive shift in most games, and it's not always the sexiest job but i'd never abandon an objective if I was the only one there.
I suppose there are few people who actually enjoy guarding, most would rather be in the 'fight', doing damage or healing, that's the sexy stuff.