Such is the way of the world. 50,000 customers willing to pay $50 a month aren't worth the trouble, especially if they're even slightly demanding. Everyone wants the 50 million users willing to put up with ads that bring in $3 a month or are willing to pay $5 or $10.
In fairness, it's probably the only way to get the coveted billion-dollar valuation. If that's your metric for success rather than operating margins or return on shareholders' equity, you don't really have much of a choice. A small company could serve those 50,000 very well and make its founders and investors quite rich, but very few people want to run a small company. It's all about getting to $1 billion and either selling out huge or going public. That status is more important to almost everyone than actually making money or creating something people like. So enjoy your Apple Music and your Pandora!