In this context, surely the whole point is that we could have taxed Musk’s wealth instead, so we have collectively paid whatever amount we didn’t tax him.
A bit less, definitely, but not zero. The US government has paid billions for use of SpaceX launches since it was founded. One could argue that the spending on NASA has benefited the world much more (e.g. free NOAA climate/weather data for research, etc) vs just increasing the wealth of privateers.