That’s selection bias, not competitive pressure raising the top level. It’s not that professional positions being so few and far between for artists raise the b

That’s selection bias, not competitive pressure raising the top level. It’s not that professional positions being so few and far between for artists raise the bar. It’s that you are only looking at the top of the competent musicians which are actually far more numerous but keep music as a hobby because there is no job there. Take a similar sample of the "best" at anything and you will find similar traits.