Well, we could do some one-off studies and hope that Excel is used properly, but why? We already have mechanisms that figure out the value of things and allocate resources appropriately, they're markets. The unviable nature of public transit suggests systematic resource allocation problems, created politically. If there were really such huge beneficial side effects, it wouldn't matter if ticket prices rose a lot, that'd just get priced in to other things like cost of goods near transit stops.
For instance maybe every ride in NY should be 2x or 3x the current price for the costs of the system to be worthwhile, but public transit is usually government owned and politicians aren't willing to bite the bullet on that.