Are PSP rare?

Excuse me, I'm curious to know, are Payment Service Providers (PSPs) considered to be rare in the world of cryptocurrency and finance? It seems to me that they play a crucial role in facilitating transactions and ensuring the smooth Flow of funds, but I'm not entirely sure if they're widely available or if there's a limited pool of them out there. Could you shed some light on this matter for me, please? I'd greatly appreciate your insights.