The investment money is gone. Record labels functioned as venture capital firms. Their bread and butter, the physical audio disc, is no longer. No other entity has yet stepped in to provide mentorship and investment capital for young, bootstrapped musicians.
The schedules of musicians do not align with the modern working world. Employers do not look highly on people who take 8 weeks off to tour. In order to make money touring, you have to be pretty well established.
Also, unlike software development, there is no 'day job' that musicians can work while saving to bootstrap their own venture. Their only option is are low-paying temp jobs, mainly in the service industry, that they must frequently quit in order to work on their craft.
And if concerts and not recorded albums are their craft, they will need to spend lots of time on the road perfecting it. But how? Practice does not make you a good stage performer. And you can't play 10 times a month in your home city and expect fans, promoters, or clubs to think nicely af you.
Sure, there are still new music artists that emerge, but nowhere in the numbers that they have in the past. It is ultimately a dying art form and those that don't see that and in fact argue the opposite, don't have any inkling of what is actually going on.