I suppose it depends on the definition of being a "Professional Musician".
Some of us would consider it being in a signed originals band, touring, recording, playing gigs etc.
The reality is being in Wedding / Function / Lounge / Cruise / Theatre settings, playing any one of thousands of cover songs on request, playing shows daily, sacrificing evenings & weekends, travelling all over the place.
I had a chance to audition for a signed band in the 90's, but turned it down as I didn't think I was good enough.