In the same timeframe, much more success has been found in improving the efficiency of renewable power solutions which are functional out of the box, easier to maintain/update, cheaper, and an easier sell.
I agree that fusion is important to research, but comparing it to the Manhattan Project or the Space Race is to forget that the world was at war when the atomic bomb was delivered from theory to reality in, what, 27 months?
The world was locked in the grip of paranoia about nuclear armageddon and the US/Russia both felt the same existential need to establish a space presence to avoid losing ground or giving so much as a hint that either side might be technologically less capable of catastrophically second striking the other.
Fusion is a notion that has been actively researched and experimented with in a time of relative peace. There's less pressure on the world because no one sees climate change in the same light as nuclear war.
The world still has conflicts, but in the minds of the West, the nations that are in conflict are always in conflict, it's just how it is out there. Obviously this view is absolutely ethnocentric and absurd, but that's the mindset.
War's just something to report on, something people almost expect to see on breakfast TV when they go to work. It would almost be eerie for them not to see or read about a war somewhere.
Thus, I would argue in the absence of existential crisis, and in the presence of the climate change narrative where words like "renewable" and "green" are easily distinguished over "less waste than fission", fusion power ultimately just lost as a business prospect to renewable energy.