I think those old proverbs (jack of all trades, etc.) look more toward stability. It may be exciting and risky to be a generalist, but specializing means you know you’ll have food on the table.

I think it just happens that generalists are either the cream of the crop, or they fall behind. For instance, in a corporate atmosphere, generalists may not climb the ladder so easily. But then again, each situation is different, so who knows!