> There's a lot to be said for generalists, or "T-shaped" people. Every single project requires a large breadth of skills all up and down the stack... and a lot of moving pieces (client, server, markup, JS, CSS, blah blah blah) that work together.

That's not really the meaning of T shaped, as I understand it. The point of the T shape is that you have a lot of breadth (the top of the T) as well as a deep depth in an area or two (the stem of the T).