Just think about how huge this country is (size and population) and the GA has less than 60 teams spread across the entire country. I think the DA tried to do the same thing with about 65 teams, but they were going to lose a few back to ECNL this year if they had not disbanded.
The ECNL, on the other hand, now has about 120 clubs between ECNL/ECRL spread out over about the same area. That's not great, but it's twice as good as the DA last year and the GA this year. I grew up in Texas and the travel in that GA region is incomprehensible to me and, to make matters worse, the GA/DPL teams probably WON'T be using buses this season for their long trips. The families will travel alone most likely to those away games and most of them are in other states. It's just too much, in my opinion, for the GA. The DA was able to convince clubs to do it for a couple of years, but maybe their small number of teams helped them decide to disband the DA given all of the travel issues going forward. That can all change with a vaccine, of course, but we have no vaccine for SARS and MERS so it could it could be a while before we get one for Covid.
Another issue for the GA is it just looks bad that many of their top clubs are eager to accept an ECRL-only invitation from the ECNL for this upcoming season. If they were truly "all in" on the GA concept, then you'd expect them to turn down the ECRL and just move forward with GA and DPL teams.
Everyone can understand FC Dallas dumping the GA a week after it was announced to return to full ECNL membership, but teams like Legends, Beach, etc. only received ECRL invites. In addition, the ECRL/GA teams like Beach told the GA their top teams would only do the GA, but I sincerely doubt that will be the case.