There were probably other forces at play when it came to the breakup of the communist Russian empire than oil. I have heard that much of it having to do with Russia not being able to keep up with our defense spending.
It was a great many things, a lot of it indirectly related to that. But also what that spending was spent on.
A lot of people to this day are still confused as to what "Star Wars" (SDI) actually was. They all seem to believe it was about "Space Lasers", but it never was. Never. Even from day 1, the main goal was to use kinetic kill vehicles to destroy inbound missiles.
But that is kind of hard to actually show in an animatic, so people would watch them and think they are talking about lasers. And even though they very clearly said "kinetic energy weapons" at 30 seconds into the above video, most people thought it was using lasers.
And in their desire to keep up, the Soviets sunk billions into high energy laser weapons. Which gave them a return of almost nothing. They had their own competing "SDI" program, that over 4 decades later has given them nothing in return for all of that investment.
Meanwhile, almost all of the US research went into things like the GPS system. And kinetic kill weapons that are the backbone for the modern PATRIOT system, THAAD, GBI, and the modern SM series of Naval missiles. Oh, the US still does research into Laser weapons, but notice it is almost a sideshow, nothing has ever gone operational.
Even more of the spending itself, it is what that spending was aimed at and resulted in. The US actually has gotten decades of advances both in the military and civilian sectors. GPS, modern satellite communications, XM radio and DirecTV, the advances in packet transmissions, all of that is based on the foundations of "Star Wars" research. The Soviets pretty much threw all of their money into a black hole that had no application for civilians.
That is a funny thing about the mindsets in the two countries. In the Soviet Union-Russia, they only thought of the end result weapon. Nothing else mattered, and any such research was so aimed at only that goal, they "could not see the forest through the trees".
Meanwhile, in the US such research was a joint Government-Corporate affair. And the corporate side was always looking at their advances and thinking "Gee, what can we do with this in order to sell it to everyday people?".
DirecTV and XM radio spun off of an early Hughes program to provide satellite communications on the battlefield. Their project was only unidirectional, but was key for an SDI era alert system. First to ground bases (DirecTV), then to mobile units (XM Radio). But in both of those, the ground locations could only receive and not transmit. They even worked out a work-around, allowing the remote locations to respond over POTS (phone system), so communication became bi-directional but response slower.
Hughes adapted that to civilian use, and that became "DirecPC".
But in the Soviet Union, absolutely no thought was ever given to improving the lives of the citizens above the absolute minimum. That is why almost their entire culture in the 1980s still looked like it had been frozen in time since the 1950s. As computer ownership in the US was approaching 50%, in the Soviet Union it was under 5%, with the majority still made by hobbyists with castoff parts like it had been in the US two decades earlier.
The most advanced "Dial-Up" service in the Soviet Union in 1991 was RELCOM, founded in 1990. And it had a whopping 20,000 users. Meanwhile, in the US CompuServe was founded in 1969. And in 1991 it had over 2 million users. AOL had over 3 million members in 1991.
Why? Because such things were simply not important in the Soviet Union. Nothing to the people, everything to the state.