Until it was realized it was more survivable and way more capable than the E3 and E2 (which one had to wonder what sort of drugged up crazy thought that was a viable option), as well as the uncomfortable issue that Space is an option, but cannot be the only one.
Space is an option..... Only for the US. Not so much for the rest of us. There really is only one company that can pull off the line of global coverage the Pentagon wants. The same one that is also building a global comms network for the Pentagon (which could (likely is) carry other sensors).
For everybody else? There's a spectrum. We absolutely can and will use space based radar for coverage over certain AOIs. But it would still take us two decades to get to the capability the Americans want to get to globally in one. In that time, and to enable expeditionary ops beyond, we need air breathers.
I don't think the USAF is wrong either on survivability. The PLAAF designed the J-20 with exceptionally long range. The PL-21 missile has exceptionally long range for a BVRAAM. The size of their sixth Gen fighters implies long range. None of this is optimized to take American fighters head on over Taiwan. Instead they are designed to fly unpredictable routes and kill tankers and emitters in the rear.
Even in a Latvia scenario, I question the survivability of manned AEWC that is any closer than say 200 km from the leading edge of friendlies. We have seen Russians kill a Ukrainian fighter at 190km using an R-37M. Similar to Chinese PL-15.
The question becomes. At what point in the development cycle does a single large manned AEWC become obsolete because the standoff required eats up too much detection range? To me the eventual approach has to be some kind of quarterback approach. Either an airborne or ground based command node using a network of drones with sensors that can get closer and are less painful to lose. I would hope Globaleye and the like are being designed to transition to that quarterback role.
The Globaleye, for us, is at best, relevant through the 2030s. We'll definitely need to have a conversation on survivability beyond that. Or at least at that point, the conversation will become public.....