It's not like there are a lot of idling cosmologist for lack of instruments right now, you'd really need to expand the set of tenured positions within the field

It's not like there are a lot of idling cosmologist for lack of instruments right now, you'd really need to expand the set of tenured positions within the field if you'd want anyone to actually use a second Vera Rubin. So "more of that" isn't a very useful position, science output isn't a linear, or even monotonous function of dollars spent.