Can you give an example of an area that late-stage investors don't support? Do you mean something like fusion research, which will obviously have payoffs >10-20

Can you give an example of an area that late-stage investors don't support? Do you mean something like fusion research, which will obviously have payoffs >10-20 years down the line? (Why don't current VCs invest in those areas, if they're potentially profitable? Just a lack of a long-term view / fund wind-down timelines?)