In their self view they ensure that artists earn money for their living, thus allow artists to survive. And there is some truth to it. Finding the right balance is hard ... but in my view they "rights holder industry" is too strong indeed.
Of course they don't do only that, they also have to spend their time crafting abusive contracts and extensions in detriment of artists and in favour of big recording companies.
They made 820 million € in revenue, 128M€ are their "costs", 692M€ of that 15% are their fees, remainingnis split between labels and artists and artists got 316.5M€, thus a quite low fraction ... and in German law the creator is theoretically stronger positioned than in US copyright.
(Now this isn't 100% fair as analysis, as some of the payments to labels go to artits, as well and labels also do some marketing etc benefiting the artist ... and then there is this weird distribution mechanism where a successful artist gets over proportionally more ... but in the end: "small" artists only get a very tiny part of the cake)