Any idea why this was? Was it just a more manageable population size? I believe the then Czechoslovakia and Hungary were similar in terms of being "better off" no?
On top of that, USSR was actively trying to incorporate newly acquired territories and assimilate non-Russian people to build the Soviet Man. Significant part of population wasn't very happy about it. Meanwhile satellite countries were busy building nation states and had less internal struggle.
IIRC, Soviet budget was much more military-oriented as well. More money towards budding regimes in Africa, Asia and South America too. Meanwhile satellite countries in eastern bloc were neutral or even received some resources from Moscow.
For example... What do people love drink on Christmas eve? Poppyseed milk! Guess why schools had mandatory dentist exams the next day...