It means we are closer to success when we see a lot more VC funding of nuclear fusion versus government (taxpayer) funding. VCs don't have the timeline or ability to lose money without much consequence or blame like the government does.
They didn't because they don't have the guts to create entire new branch of science.
Once the government has built research laboratiries, trained physicists and engineers, built prototypes, waited untill those engineers come up with viables plans, then the VC are ready to swoop in and take all the credit.
Thats fine if Venture capital can't make 60 year investments. Whats not cool, is everyone else buying the narrative that we don't need government funding for fundamental research, that VCs will solve all problems in the world as long as we let them run wild and don't tax them