I would be a bit more careful in disregarding the role of the weakening USSR. It’s true that history is never monocausal and it’s certainly not the weakening of the USSR alone that led to protests (you could even argue that the first protests in Poland in 1980 had nothing to do with the USSR) and later revolution but I think it played an important role. East Germany certainly hoped for support from the USSR and was denied the same by Gorbachev. It was certainly never completely certain that the USSR would not intervene but it was a lot more certain than in 1956.