Who was more responsible for the end of the Cold War and the Soviet collapse?

[Middle-aged Europe]

I see "planned economy" isn't on the list.  I suppose Gorby out of the sh**tty options listed, but he was just in control of the timing of it....the collapse was inevitable.

Actually, Soviet collapse was not inevitable. A different leader could have just liberalized the Soviet economy without giving the Soviet people more political freedoms. Thus the U.S.S.R. would have been similar to China today (a capitalist dictatorship) and would have survived and thrived for at least several more decades.

Of course, a major difference is that only 51% of the Soviet population were ethnic Russians, while China is made up of 92% Han Chinese.

Holding the PRC together is far easier.

[Middle-aged Europe]

However, about 70% of the Soviet population was made up of Slavs. That is a pretty large majority.

And almost 90% of the population of Yugoslavia was made up of Slavs...

Those were still distinct ethnicites/nationalities though.

The PRC on the other hand has one large distinct ethnicity.