They should add the unaltered original trilogy to their streaming platform and promote it to Star Wars fans that you can only watch it exclusively on Disney+
I mean if they wanted more people to join, that would be a way to do it.
Those things would also appear on torrents before you could say GOUT.
Only putting the earlier versions out on physical disc and maybe then only on 4k UHD might not prevent piracy of it altogether, but it would be a helluva deterrent.