That's correlation, not causation. It proves nothing whatsoever as it relies entirely on hypotheticals (e.g. would RU have done better than 1-6 if RU had built a new fieldhouse at the same time as MD - which an unanswerable question).
MD's fieldhouse might have been a differentiator prior to the NIL-era. But in the NIL era, I don't think it matters much, if at all. A player (and their family), considering MD and RU, is going to first compare NIL offers, then compare stuff like coaching, location, program history, academics (the parents more than the players in most cases), the locker rooms, the campus, etc. The fieldhouse is likely to be one of the last, if not the last consideration, if considered at all.
If you want to use hypothetical arguments, then I'd argue that, had NIL existed back when they built the fieldhouse, and had MD redirected all the funding for a fieldhouse to NIL instead (while nothing changed at RU), then we'd be 0-7 with bigger blowouts instead of 1-6. Sure I can't prove it. But neither can you prove your assertion about a fieldhouse's value in recruiting to RU in the NIL era.
A player for whom the fieldhouse is a determining factor is probably not a player I'd want on my team because it reveals a likely high level of pettiness in the player's personality. And pettiness in players is not great for team chemistry.
