If you want to get good at something, decide on what that field of interest is, and dig in. Only through specialization can you get really good, the thinking goes.
David Epstein begs to differ, and does at length, in the book Range: Why Generalists Triumph in a Specialized World. Dabbling in a lot of interests instead of staying in a silo pays dividends, he points out. The author brings in the evidence to support his position.