The correct number of staff for a successful station in 2024 is probably right in the middle of the skeleton crew of most for-profit and the over bloated number of non-for-profit.
The number doesn't matter. It's what they do. Generating unique local content takes more staff than playing records. WBUR isn't owned by a corporation where 6 stations share support staff. So it's a very different kind of operation. WBUR is more like radio used to be, when companies could only own one or two stations in a city.