Especially one you can't even get into contact with, besides automated rejection messages.

You're describing every B2B business. The issue is the monopoly power of Youtube - Durable B2Bs will have a list of quality partners they can turn to.

Unless you are prepared to roll out your own video-delivery + user subscription infrastructure, what's the alternative here?

It is the case for many businesses. This relationship, however, is quite egregious.

Can you name a business that depends on zero other businesses? What a completely wild take.