Well nothing is free. You’re the product on YouTube.

By the same logic nothing on the fediverse is an alternative, as it runs on donations from users which is basically a subscription model with built in welfare for those not able or willing to donate.

Given that nebula videos are more difficult to produce than rambling text posts, it makes sense to be more stringent about the subscriptions. I’d say therefore it’s very much within the spirit of the fediverse as profits are given back to the creators.