Feel free to call this a crazy idea. But until we have a reliable treatment/vaccine, I think the only practical way to get productions back up and on time is to not just do a closed set, but a closed lot; now everybody gets a trailer, not just the stars.
The entire cast and crew live on the premises for the duration, (including one to two weeks at the beginning to clear everyone coming in) and nobody gets to leave unless they’re not coming back or production is wrapped. Everybody. From the Director to the Craft Services people.
You don’t do location shoots, you shoot those virtual and green screen, or, those are done last, after everything possible is shot “in the bubble”. Of course, this is hella inconvenient. And expensive. OTOH, your production is… producing. You have new product to sell. And it might actually in some ways go faster than the minimalist start-stop methods, if the union and studio get creative on the hours.