Just my $0.02 as a Utah native who has seen the changes that have happened to SLC, PC, the local canyons, and the local ecosystem over the past 50 years:
I'm happy to see any system put into place that helps reduce the number of single-occupancy vehicles going up and down the canyons that feed the water system of the Wasatch Front. If it's in the form of a per-vehicle toll (and preferably one that uses gross vehicle weight and engine type as its calculation), a bus rapid transit system (one that I favor over all others), or some kind of aerial people mover (i.e. a gondola or tramway, which is not ideal or equitable, or even a subway using renovated mining tunnels), something needs to be done to help preserve the environment of the Wasatch.
If the toll is too low it won't keep the masses away or pivot them toward UTA as a way to get up. If it's too high it'll backfire. If it's in just the right ballpark and the funding is used to help subsidize UTA's bus service (as well as to help preserve the watershed) then I am all for it.
Sure, tailgating won't be the same - c'est la merde. But if it means the canyon ecosystems can be better protected, if it means getting rid of the "red ribbons" of bumper-to-bumper traffic (with all of those vehicles idling and spewing toxic emissions into a relatively captive atmosphere in the canyon areas), if it means the thick crowds at the lift-served areas are, well, less thick then I'd call that a win.
I know that the U.S. is a car-centric culture with a built environment that perpetuates it. The mountain west is even more beholden to the primacy of private cars. Now there is a chance for one cluster of ski areas to take a move similar to what has happened in many European ski enclaves: moving toward a less damaging model of moving people around.
It's time, folks. We can complain about it until we are blue in the face but this is a good move in terms of helping keep Utah's ski country skiable.
Just my $0.02 - YMMV.