"One size fits all" is never a sound strategy. The "current crisis" is not an exception. People will simply refuse to comply if they think it's stupid.
What's good for The Peoples Republic of Maricopa and Pima is not good for Mohave, no matter how one chooses to slice it. The Governor did this because the mayors of Phoenix and Tucson demanded it for everybody else, when nothing was stopping them from doing it to their own jurisdictions. Classic leftist thinking: Punish everybody.
You are correct. And the only thing this strategy yields is a delay of the inevitable at a massive economic cost. We can't quarantine ourselves forever. At some point, we have to rejoin society and confront the risks and dangers associated with the end of isolation, whether that happens today or a year from now.
We should learn from history. When a polio outbreak occurred in some town in North Carolina, they didn't shut commerce down in Tennessee, Georgia, and South Carolina. Our leftist one-size-fits-all response has been completely asinine.