A little further back than that, but not much further. Frank Sinatra, maybe. With radio and recordings, for the first time a musician could get revenue from people far away.
"In my own profession, writing compilers, you simply can't sell them anymore."
Compilers, operating systems, browsers... Maybe software as an industry only had a limited lifespan. In the early IBM mainframe era, machines were expensive, vendor-provided software was usually included, and there was not much of a third-party software industry. Now, software is very cheap, and ancillary to advertising or services.
Internet downloading removed all the friction, and prices went to zero.
However, there's still plenty of opportunity doing service, maintenance, custom work, training, etc.
The "build it and they will come" is a stupid Hollywood fantasy. Even the Beatles went nowhere until they hooked up with promoter George Martin.
So incredibly true.
And even whenever I do try and talk about my software, people usually perceive it as an attack on competing software (you can't say why someone should use your product without implicitly stating why they shouldn't use someone else's); or as shameless self-promotion and advertising (even though it's all FOSS) =(
In my own profession, writing compilers, you simply can't sell them anymore. That hasn't deterred me from continuing to do so, I just adapt and find other ways to make a living from the business.