The issue with this line of reasoning is that money is generally not going to solve the problem of people barely surviving. In the vast majority of cases, sociopolitical issues are the root cause and throwing money at things doesn't really help. If you don't believe me, look at the history of aid to sub-saharan Africa. So there's no reason we can't both spend billionaires' money on space development and fix terrestrial problems with social and political reform.
And if you want to argue that billionaires only became so wealthy by exploiting people... well, yes, and? Their wealth already exists so the options are 1) they spend it on stupid stuff like more yachts and mansions, 2) they spend it on humanity-advancing things like space exploration (Musk/Bezos) and philanthropy (Gates), or 3) we have bloody revolutions to claw it back and hope for the best.
And if you want to argue that billionaires only became so wealthy by exploiting people... well, yes, and? Their wealth already exists so the options are 1) they spend it on stupid stuff like more yachts and mansions, 2) they spend it on humanity-advancing things like space exploration (Musk/Bezos) and philanthropy (Gates), or 3) we have bloody revolutions to claw it back and hope for the best.