I think what will happen moving forward is a coach's closing lineup will get pulled early in the 3rd quarter, and both coaches will ride the reserves for the majority of the 3rd and partially into the 4th. And then their closing lineups will finish out.
You said a lot of truth there but a coach asking Bron, Kawhi, KD, Steph, Giannis, Embiid, etc to sit down for a few minutes "midway" through that kind of intense 4th quarter when the game can literally be decided by a quick flurry... i can already see the overblown controversy if Steph is forced to sit for Kemba Walker and shyt goes terribly wrong for whoever team they're on.
It's the blessing and curse of running no clock tbh