Reagan wanted to end the Cold War, not win it. He spoke of those "godawful" nuclear weapons. He thought the Soviet economy was in too much difficulty to compete in an arms race. He thought that if he could first cure the stagflation that afflicted the US economy, he could force the Soviets to the negotiating table by going through the motion of launching an arms race. "Star wars" was mainly hype. (Whether or nor the Soviets believed the arms race threat, the American leftwing clearly did and has never got over it.)
Reagan had no intention of dominating the Soviet Union or collapsing it. Unlike Clinton, George W. Bush, and Obama, he was not controlled by neoconservatives. Reagan fired and prosecuted the neoconservatives in his administration when they operated behind his back and broke the law.
The Soviet Union did not collapse because of Reagan's determination to end the Cold War. The Soviet collapse was the work of hard-line communists, who believed that Gorbachev was loosening the Communist Party's hold so quickly that Gorbachev was a threat to the existence of the Soviet Union and placed him under house arrest. It was the hard-line communist coup against Gorbachev that led to the rise of Yeltsin. No one expected the collapse of the Soviet Union.
The US military/security complex did not want Reagan to end the Cold War, as the Cold War was the foundation of profit and power for the complex. The CIA told Reagan that if he renewed the arms race, the Soviets would win, because the Soviets controlled investment and could allocate a larger share of the economy to the military than Reagan could.
Reagan did not believe the CIA's claim that the Soviet Union could prevail in an arms race. He formed a secret committee and gave the committee the power to investigate the CIA's claim that the US would lose an arms race with the Soviet Union. The committee concluded that the CIA was protecting its prerogatives. I know this because I was a member of the committee.
American capitalism and the social safety net would function much better without the drain on the budget of the military/security complex. It is more correct to say that the military/security complex wants a major threat, not an actual arms race. Stateless Muslim terrorists are not a sufficient threat for such a massive US military, and the trouble with an actual arms race as opposed to a threat is that the US armaments corporations would have to produce weapons that work instead of cost overruns that boost profits.
The latest US missile ship has twice broken down and had to be towed into port. The F-35 has cost endless money, has a variety of problems and is already outclassed. The Russian missiles are hyper-sonic. The Russian tanks are superior. The explosive power of the Russian Satan II ICBM is terrifying. The morale of the Russian forces is high. They have not been exhausted from 15 years of fighting without much success pointless wars against women and children.
Washington, given the corrupt nature of the US military/security complex, can arms race all it wants without being a danger to Russia or China, much less to the strategic alliance between the two powers.
The neoconservatives are discredited, but they are still a powerful influence on US foreign policy. Until Trump relegates them to the ideological backwaters, Russia and China had best hold on to their strategic alliance. Anyone attempting to break this alliance is a threat to both Russia and China, and to America and to life on earth.