I think that all developers start out as specialists and over time become generalists unless they decide to make a concerted effort to remain a specialist. How many DBAs have had multiple comical instances to report over beers with other DBAs about some idiotic process or SQL code written by a developer because they couldn't be bothered to learn anything about a database (the comic Raw Materials comes to mind here)?

I also think that if you're a specialist, and all you've got is a hammer, everything looks like a nail. A company needs both specialists and generalists, or they are losing out on the big picture. Projects can't be siloed, and good communication can avoid this, but how many projects really run that way?