I don't believe this is the case. I'm pretty sure there have been "hard" limits so far on what can be achieved. I'm not a physicist, not even close but as I understand it two issues remain. One is that sustaining the fusion reaction has been problematic. I believe the longest sustained reactions have been less than one second. Two is that currently we have to put more energy into creating and sustaining the reaction than it yields. These two things make this categorically different than a challenge like building the hyperloop which as far as I know didn't have any unsolved science or engineering problems.

Again, I could be wrong on my physics but as I understand it, fusion power is still a question of "is it even possible" whereas the hyperloop was more of a question about socioeconomic will.