Can dr Insane elaborate on why are the two companies suddenly almost equal in viewership
Well, sports was hurting both shows, it seems the world series took more viewers from NXT then AEW, chances are both will increase again on Wednesday though AEW might have a higher boost due to Full gear, chances are with sports mostly done for now on wednesdays and things slow down both shows will get more viewers.
It was a given both shows would increase but we didnt know how much, chances are as i said both will increase but now its a matter of how much and will NXT take the lead or stay right behind AEW. as you saw they were within 1.1% of eachother, just 9.000 viewers which on the grand scale of things is very very close, AEW did win in the all important demos though and argueably those are the most important.
As for a direct answer, not sure, likely sports took majority of NXTs viewership and not as much from AEW, so now they got their fans back, for now. I suspect AEW will remain in the lead due to hype from Full Gear, most shows get a boost after a PPV so that should apply to AEW.