It was not bloodless and Gorbachev did send tanks and army into breakaway republics [1][2][3], the soviet union was simply too weak to do anything to stop the movements to break away from Russia. Russia even lost the war with Chechnya in early 90s, which shows just how weak they were. It wasn't until the west helped rebuild Russian economy (mostly based on fossil fuels) that they were able to revive their imperialistic ways under Putin.
[1] https://en.wikipedia.org/wiki/January_Events#January_13 [2] https://en.wikipedia.org/wiki/Black_January [3] https://en.wikipedia.org/wiki/The_Barricades