Fujitsu actually does sell their A64FX processors. In fact, they are running in one or two European super computers[1][2]. Still, that's not to say that buying them Fujitsu is easy and/or straightforward.
[1]: https://www.hpcwire.com/off-the-wire/fujitsu-selected-to-del...
[2]: https://www.youtube.com/watch?v=yInhWFztvXs