They can sell API access via transparent pricing.

Instead, many, many websites (especially in the music industry) have some sort of funky API that you can only get access to if you have enough online clout. Very few are transparent about what "enough clout" even means or how much it'd cost you, and there's like an entire industry of third-party API resellers that cost like 10x more than if you went straight to the source. But you can't, because you first have to fulfill some arbitrary criteria that you can't even know about ahead of time.

It's all very frustrating to deal with.