What good is starting a civil war you can't win and in which you will last less than a year and end up dead?
My point is, the party/StB/KGB calculated (at least in Czechoslovakia - there are their own meeting notes about it) they wouldn't be able to win, and so decided they would rather steal some stuff than destroy it (or let the rebels destroy it). If they wanted to win by force - and initially they wanted to, until they understood the scale of the rebellion - they would need much bigger forces, but that was impossible to arrange, and not for lack of willingness.
They actually deployed the army (both CzSk and Soviet troops) and police, but the rebelling masses were way too overwhelming and they chickened out - there are videos of them going/rolling tanks backwards away from the enormous masses of people (easily hundreds per one troop, not even possible to kill them with your Kalashnikov). If they fired the tank, they wouldn't last 5 minutes and their death would've been nasty. What changed from 1968 in CzSk and from the situation in China was the scale of the rebellion - in 1968 only tens of thousands of people protested, in 1989 it was millions, and each incident (not like there weren't any) caused much more people to rebel instead of suppressing it.
And there was no silence out of Moscow. There are records of USSR-CzSk phone calls about this, and it was definitely not silence nor "we won't do it because it's bad" but "we can't do it because we're out of money, you're on your own BUT DO SOMETHING OR ELSE" (the CzSk side was asking for air support and so on). I assure you that if they went with force all the communist party members, StB/KGB agents and Russian troops would've been hanged afterwards - so the only remaining option was to let it happen and this way they all survived and some even thrived (like for example Andrej Babiš).
Gorbachev's "democratic-communist" (hah, what an oxymoron) Soviet Union could've never worked without the satellite states which supplied most high technology, a lot of important natural resources, etc with dictated prices USSR could afford, so I really don't think he'd just let it go if he had any other option. Certainly the phone calls didn't sound like they were happy about it or that it was the plan all along.
Overall, I don't buy the Gorbachev==good view. Perhaps he let the fall in DDR happen, but probably only because he was busy trying to keep other parts of the empire such as Hungary and the Baltics. He might've been better than the previous leaders, sure - but who isn't better than Stalin and the party? He was still an imperialist even to the modern times, and wanted to force communism (and all the associated baggage) down the throats of his subjects even though the people were demanding the end of planned economy. That makes him bad in my eyes regardless of whether he decided to let the fall happen or not, anyways. Certainly nobody to be fond of, and probably just a case of being at the right time at the right place - it's not like he could've said anything else than he said without being thrown out of the window.