I think the M-3 has a valid role in everything it can resupply, towns or factories. When I'm on, unless it's squad night, I spend a few minutes running resupply to factories. Maybe someone else thinks it okay to have important strats down in the 30s%, but I don't. That's a good way to lose bases and keep yourself having to fight uphill when your ammo, ack, and radars are down for an hour or more. If I can get there faster then flying, I'll take an M3; if not, a goon.
Two days ago I was doing this and was the only one doing so. I think I ran 4 boxes, maybe 20 min or so. Then I spent almost 3 hours flying and fighting. So if someone is trying to make the case that the world will fall apart and no combat will happen unless we boot M3's in a supply role, I simply can't accept that as reasonable. I was one out of 50 or so people doing resupply for a few minutes, the rest were in the air.