From what I have seen as an occasional musician and running sound is that these days most musicians are not willing to make the sacrifices and put in the time, they will not take that poorly paying weekly gig and spend a year or two refining their performance and learning to read the audience which is a major part of making it in music.

I know a good number a professional musicians who have made it to the point where they can live off of music without constantly working, every single one of them started out the same way, playing every single show they could regardless of pay or location. This started to change around 2010, the venue I used to do sound for primarily targeted musicians who were starting out either on the local scene or national scene (just starting to tour and trying to make a name out of their home town), by 2015 music was mostly done there because the 19 year olds who had only played a few shows were not happy with $25 and a meal to sit on stage with their guitar for an hour, they wanted $100 and expected to play to a full room.

The boom in home recording also probably played a role, the starting out musicians are often resistant to it because they see it as pedestrian and not for serious musicians, musicians record in studios, not at home. Record on anything anyway you can and bring a few dozen copies to sell at those poorly paying gigs.