Soviet's economy collapse started long from before his time. The coup basically ended any fragment of influence he still had. I watched a documentary about him and yeltsin in a cabinet meeting. Gorbachev walked alone, while the other ministers all walked with Yeltsin. Yeltsin also treated him with disrespect, rebuked him in front of others. Even if he wanted to hold Soviet together with iron hand, he basically had no power to do that. Soviet disintegration was mostly Yeltsin's fault in my opinion. He had the power, but he chose to let Soviet collapsed so he could grab power.

Thankfully, Deng Xiaoping chose different approach in 1989.