“Find a niche”. This is a pretty standard bit of advice. In a job market over-crowded with musicians who are really good, skill alone won’t get you the job any more; you have to find a way to differentiate yourself. Usually that means finding something really specific to be really good at.
I’ve noticed that actors are beginning to do this to promote themselves. There is perhaps demand for diverse and talented actors who can create a wide variety of characters flawlessly. But how can an actor compete with Meryl Streep for example? They can’t (or at least would have a hard time doing so); they have to find a niche. Trying to be really good at everything can stretch a person’s time and resources too thin; they end up just being mediocre at a lot of stuff and never get work. Find your strength and play to it.
Nick Offerman, for example, basically plays himself on Parks and Rec. He gained a certain degree of notoriety by publishing in Fine Woodworking magazine so being a woodworker became part of his character on TV. He then released a comedy special in which he asserts values which are similar to those of his Parks and Rec character. In the special he makes frequent references to the show and to his wife, Megan Mullally (who acts alongside him is Parks and Rec) both of which are intrinsic parts of his niche brand.
Rainn Wilson, similarly, just announced a memoir which is billed as having a “foreword by Dwight Schrute”, his character on The Office. His characters have been famously, painfully awkward and thus his book shows how his awkwardness gained him notoriety.
Rather than spreading their time and resources thin by developing multifaceted acting portfolios, they have spent most of their time playing up their strengths and have been wildly successful doing so.
Musicians can follow the same advice. Not everyone can be Joshua Bell or Yo-Yo Ma. This is not to say musicians can ignore the classics; they are important. But if you try to just be really good at playing standard classical music, you will probably have a hard time competing with the Itzhak Perlmans of the world.
Rather than trying to be Meryl Streep, find your Nick Offerman/Rainn Wilson quirk and use it to develop your niche career.