And once we had the Death Star in Episode IV, there is no reason not to continue the technology. You complain about the appearance of the Emperor’s fleet out of nothing and yet in ROTJ we had a second (and larger) Death Star show up the same way. I really get the sense that you do not carefully think how the OT may done similar things before you judge the ST so harshly.

Pointing to what is widely considered the weakest part of ROTJ, namely the reappearance of a Death Star is hardly a good defense for the ST reintroducing superweapons two more times. Additionally, the second Death Star at least has a function in the story, while in TROS they are just an artificial way of adding tension to a pretty boring space battle.