I remember this being talked about at an open conference a few years ago, and how it was a field for revenue generation. That said, it seems to be the applied approach, where anything supporting 8k is licensed based.
However, the plugin you are using is customizable... And looking through the base code, the actual viewer handles 8k, at least, there is nothing suggesting it can't so it must be the plugins version it uses or viewport limitations in development of the plugin.