You are assuming Utah and Idaho do not join the Pacific states. But very likely they will.
You are also assuming the schools open, rather than being online, which is not the way things are looking even with opening up.
In the broader picture, what California is announcing is what almost all public Universities and many private Universities that can afford it will do, regardless of locale. New York's lock down is already extended longer than California (excepting LA County), and the Northeast is likely to follow. For example SUNY schools may be one of three things:
1) online only
2) start online then move to on campus to finish
3) delay start of year until October or November to be on campus
https://www.bupipedream.com/news/116865/...of-action/
This is not a California only thing, not a Pacific Coast only thing.
Others are planning to open (most Ohio schools, University of Arizona at least, many in the South). The question is will stadium events occur? Will football occur? It doesn't seem likely, as athletic departments depend upon gate for much of their revenue. The G5 especially, who only get a small portion of their money from media. Also restrictions on social distancing will still be in place, and it's hard to see how you can hold practice. (For example the NBA had 18 teams eligible to open facilities, but only 2 have, and those only 1 or 2 players at a time; certainly not regular practice.)
As for the Pac-12, Arizona plans to open, but Athletics probably not. The MWC commish doesn't think Football will happen or any fall sports. This even though 2/3rds of his schools are in the "open" Mountain States. Is it any better anywhere else?