I'm finding the opposite, it seems to be more with players who had exposure to previous editions. The younger folks I've gamed with don't seem to have any expectations. I've actually seen several friends I've known for 10 or 20 years move to this type of play style, and if they are regular MMO players, the problem gets far, far worse.
There's maybe been a pendulum swing going - assuming you're playing the latest ed, that is. Last edition, the game got very group-focused - group tactics, abilities that helped allies, defined 'roles' that contributed to group success, and involved 'set piece' combats that called for all that. Latest edition generally tries hard to be everything the last one wasn't, so none of that - individual tactics & abilities, self-contained characters, small/fast combats that don't require synergy to defeat.
That said, it's still mostly a style thing. You can support eachother and work as a team if you want to, the system just doesn't give every class tools to do so, specifically.
How do I deal with players like this? Kick them out? On the other side of the coin, what if I'm stuck at a table (or worse, a table at a con) with one of these people?
As a DM, I believe it's better to give players what they want rather than 'teach' them the 'right' way to play, but that's just me. You could give them harder challenges that require teamwork to overcome - it may just be that they're not engaging because it's 'too easy' (not a rare complaint lately). On the other extreme, you could give them more scenarios that offer a chance to compete, even while working towards a common goal. Making who scores the 'killing blow' on a monster important somehow (exp, renown or some more tangible reward, like finding a magic item on it or receiving some special ability from it's 'heart's blood' or something), for instance, means they cooperate, but are also racing eachother.
When you're playing? Play the support character, but only support the PCs that show a glimmer of teamwork? Or, on the other extreme, build your own self-contained character and ignore 'em?
It really depends on the individuals. You might do better to find a different group, if that's not an option, you might try asking some leading questions and try to figure out what's up, maybe point out some possible teamwork tricks.