This whole thread is about how asking for donations is a big fail online.
Yet, there's no lack of street performers in most major metros. Whether that is people in superhero costumes on Hollywood Blvd, or street dancers in times square, they all seem to be doing fine off donations.
There is something about the online "free duplicate copy" concept that just makes value dissappear
All websites are not comparable to Times Square or Hollywood Blvd, in terms of how much attention they get. You also don't see performers in 99.99% of cities, even in other areas of the same city like NYC and LA.
We're a social species that evolved in tribes. Street performers probably do a better job of stimulating that sense of tribe than abstract interactions on a web page do.
Of course we know these services aren't really free; Google and Facebook still run their services on physical servers that have hosting costs. But by making their apps free and finding alternative revenue streams (i.e. selling data), they can set norms that harm competitors with less capital while making it easier to adopt new users (and collect more data).
They may be doing fine, but I bet that, for most, donations aren't their only source of income and they probably have another job.