Gotta agree with Collispo. In all technicality, the PT did expand the story of the OT and build upon the existing trilogy while the ST is simply a continuation or in a way just a soft reboot.
But yeah, you can say technically the same thing about ESB since Star Wars did leave things off so nicely.
And at the end of the day it doesn’t matter to me. I don’t watch the PT and I really enjoy the ST. That’s all it comes down to.