What are the barriers to getting paid, in this era of online streaming and PayPal?

Finding people who pay you.

And good luck surviving off the scraps you get for streaming fees

low barrier to entry lowers cost, so this is exactly the desired outcome

But also quality. For example, YouTube pretty much forces people toward lowest-common-denominator filler content, because if creators don't upload new content frequently enough they'll drop out of recommendation lists even for subscribers. Creative software tools are easily available and distribution is free, but YouTube has a monopoly of information and so creators have very little insight into what/when/how people see the creative product or how revenue is calculated.