Who do you think creates all the stock value for social media companies? Do you think such users should be equally outraged that their social media site has billions in market capitalization but paid them $0?
Effort doesn't entitle you to money. You could get a phd in mongolian basketweaving but that doesn't mean you should be entitled to a decent living from selling baskets. If the economics are not there (ie. the average person not valuing music at more than $10/month, tons of artists lining up to drive down the price) but you go into it anyways, you only have yourself to blame.
um, many users are absolutely. this is still one ot the most frequent critique of these sites. for example Reddit with its IPO, and their bossing around of their unpaid mods, and so on.