how did you come to this conclusion? The full product can used for free in perpetuity. you only ever pay if you want support, or feel that you would like to support the project/developers. it doesn't get much better as a licensing model.
Found my answer on Reddit of course lol....Well, from the fact I don't see anywhere where it says "Proxmox VE the Free Open Source Hyper-Visor" Maybe I'm just blind lol. You just pay for support subscription if you want.
Joedub
Might want to edit your post, or remove it if you can. Not a good model ... if you want to make a decent first impression here.