The special thing about plex for me is it is effortless. I run the server, and without any port forwarding it just works. Then my in-laws can sign up, and just like that they can stream that movie I totally own legitimately... And I don't need to walk them through entering my IP, a port number. They just sign up and it works.

All of that has a cost. It costs money to maintain, it costs money to develop, it costs money to host.

It's a commercial product. They have been inching more towards monetizing their product for a long time. Being able to pay for a lifetime is a huge win imo. I wish more companies offered that.