Actually, it's long past time to give up on fusion, at least DT fusion. It's been known since at least the 1980s it would have lousy power density. DT fusion's putative advantages don't make up for that, nor for its grave operating issues (frequent replacement of major components and serious reliability/repairability problems.)
It will not have to compete with fusion in the late 2030s. It will likely never have to compete with fusion. Fusion is just ridiculously bad from a practical point of view.
D-T fusion is not as clean as is touted, and the economics just aren't ever going to make it viable compared to ever-cheaper solar, wind, batteries/energy storage, etc.
Better fission designs OTOH are worth pursuing, and also deep geothermal, and maybe one or two of the CCS options though they seem a bit greenwashy.
Fusion would be a perfect candidate. We pretty much know that it will work, we know it would yield big benefits, we just need a lot of money to work out all problems.
If things are not making sense, you need to reexamine your assumptions. I will argue that fusion actually doesn't have much potential, and the relatively low interest in it (as reflected by money being spent vs. alternatives) reflects that.
I think that 50 years is a reasonable timeframe to give fusion the possibility of delivering results. But I agree with you, it's pretty much impossible that anything will come out of fusion in the coming 10-15 years, despite the publicity we keep hearing lately.
reply