Individual instances could theoretically monetize if their owners wished, they could show you ads, sell your data, sell you merch, sell the instance to a third party, all the same strategies as any other internet institution.
The Fediverse as a whole cannot, though, due to its decentralized ownership and development structure.
They could always do unidirectional federation and only take feeds from others but not send their updates out and make it walled off for a subscription.
Individual instances could theoretically monetize if their owners wished, they could show you ads, sell your data, sell you merch, sell the instance to a third party, all the same strategies as any other internet institution.
The Fediverse as a whole cannot, though, due to its decentralized ownership and development structure.
They’d need to grow big enough to turn off federation without much loss.
They could always do unidirectional federation and only take feeds from others but not send their updates out and make it walled off for a subscription.