you can answer it in regards to kpop or even main stream pop musicians
Over the years there are alot of pop artists who do well musically and build a brand for themselves. But then they use that brand to promote their other projects and put music on the back burner. Acting, perfume and makeup line are among the top activities pop stars branch off too.
I'd say in main stream scene, only Taylor swift have been a full time musician.
So what's the minimum musical activity level for you to consider someone full time musician?