I-80 and I-70 were made to increase the utility of the East Coast and West Coast. The Mountain West it growing fast and new considerations need to be made.
Denver was small at the time and got bypassed by I-80 and Salt Lake City was small and got bypassed with I-70. I totally understand that most the people using I-70 are doing the LA to Denver route, but a California Bay Area route to Denver (a route that basically doesn't officially exist), seems useful as well.
Look at any midsized city in the Midwest and East and their connectivity with Freeways. Now consider the fact that the State of Utah will have about 4.2 million people here in 20 years with over 80% of those people living in Wasatch Front Metro. Denver will continue to grow as will Boise. I think it's strange that three of some of the fastest growing metros in the US aren't better connected. Extending I-84 from Boise to Denver alleviates that problem. Let's not settle for Price and pick a route that actually goes through a place people would like to travel. I don't think state freeway inter-connectivity is what makes cars bad (I actually think that is when they are most useful), it's tons of belt loops and expansions in cities that tend to destroy urban life.
When I go to Denver I end up taking I-80 a lot of the time, because it's not dangerious and you can SPEED. In short, I say starve out Wyoming and share the East-West freight that normally travels through Utah via I-80 with Denver.