In 1961, a new redenominated Soviet ruble was issued. It maintained exchange parity with the Pound Sterling until the dissolution of the USSR in 1991. After a new leadership, headed by Leonid Brezhnev, had come to power, attempts were made to revitalize the economy through economic reform. Starting in 1965, enterprises and organizations were made to rely on economic methods of profitable production, rather than follow orders from the state administration. By 1970, the Soviet economy had reached its zenith and was estimated at about 60 percent of the size of the USA in terms of the estimated commodities (like steel and coal). In 1989, the official GDP of the Soviet Union was $2,500 Billion while the GDP of the United States was $4,862 Billion
The USA was the stronger country but the Soviets were competitive with US military technology.
The collapse of the Soviet Union and the US introduction of precision weapons enabled the US to have a vast military dominance from 1990 to today.
China is still behind the USA in several technological areas. In particular with large airplane engines and with aircraft carriers.
However, the gap is closing and China is competitive with the United States on overall scientific research budgets.
Europe was able to mount a program to create Airbus and become competitive with Boeing and has continued to match Boeing airplane technology.
There is no reason to think that the US will be able to create a sustainable military dominance like the 1990 to 2015 period while China is an economic and scientific research peer.
Any leads will be temporary and copied by the other.
China is still projected to average 4-6.5% GDP growth for the next decade while the USA is projected to be at 1-3% growth.
China has surpassed the USA on purchasing power GDP and will likely surpass the USA on nominal GDP in the 2025-2030 timeframe.