I don't know how it was in the rest of Eastern Europe, but for instance the East German government was much more 'conservative' than Gorbatchev and heavily opposed to perestroika/glasnost. If Gorbatchev wouldn't have left Honecker hanging dry, Honecker would have welcomed the Soviet tanks against his own people.
You don't need to be able to compete with the US military technology to kill unarmed protesters. T-54s will do just fine.
You don't need to be able to compete with the US military technology to kill unarmed protesters. T-54s will do just fine.