Agree entirely - and some areas like the Arlberg don't even offer a local area only pass. Layout is the fundamental - Places like Portes de Soleil are huge but if you're somewhere like Les Gets you aren't going to be getting to the furthest reaches of the Swiss side without making it a specific mission - and that takes the joy out of sessioning a particularly fun slope you find on the way or taking interesting diversions.
While conceptually a combined Wasatch isn't any bigger than a big Euro combined area there already seems to be enough "commuting" cattracks in existing resorts to make say a Canyons base to Snowbird journey a bit of a mission to me. Something that tourists might do as a one off "challenge" but not a daily practicality.
Yeah, a connection between Deer Valley, PCMR, and Canyons would be a pretty standard layout without too much of a hassle. And even getting to Brighton and Solitude might not be too bad with a peak-to-peak or something. But getting all the way to Snowbird from the Canyons would be very time-consuming.
If the whole thing is done, then the most convenient base location if you want to ski the entire area over the course of a week would probably be Brighton/Solitude.
Interesting point given that Deer Valley bought Solitude relatively recently and that's the only area in BCC that has a resort village with lodging. Isn't there already free shuttle buses if someone is staying at Canyons to get to Deer Valley?