Architects and Engineers for 9/11 Truth - 990 Tax Returns, Employee Compensation

[Oystein]

I wonder if this decline was in part due to the illness and death of Ed Asner (TV Star), who died in August 2021. I suspect he was responsible for a chuck of the individual contributions.

I have seen no evidence for this.
In past years, their form 990 would list by name a few individual contributors (usually themselves organizations rather than individual persons) and their contributions, but I don't recall anything pointing to Asner.
I have seen some rants by the likes of Andy Steele or Craig McKee blaming certain others (Ted Walter, Bill Binnier...) for certain problems in the post-Gage era, but no mention of Asner and the rapid decline in funding, as far as I recall.