We definitely should investigate. No argument there. It just won't make a difference. At this point, they have gotten away with it, and the opposition did not put up a fight. They are not all of a sudden going to start putting up a fight, when there's no way they win that fight. (But realistically: they are bad at putting up fights over things in the first place, which is how we ended up here - the party with no moral qualms about much of anything ran roughshod over them)
I agree with you it's likely pointless. I'm not arguing that "this information will change the election." That said, I do care about election integrity and the more evidence we have of fraud the more we can (theoretically) correct for it in the future.
I'm very much of the opinion there's going to be a violent civil war before the decade is over.