Early on, it was the medical workers that were in the prime jeopardy category. There weren't that many people infected, but those that were sick ALL went to the medical workers. As the virus progressed, both the jeopardy categories and the available of PPE changed....more and more people got infected, so the person-to-person contact levels were higher, and because there were no effective Federal mandates (remember the famous "You are on your own" statememt?).
Yes, if we'd had unlimited PPE at the outset, a combination of distancing and masks might have been the right answer...especially if there had been strong Federal guidance instead of the P and the V-P dancing about in fairyland.