REALITY - and this goes along with what Karin said, even if the old GNR had a reunion gig (for the money), it would be Izzy, Axl, Slash, Duff, Matt, & Dizzy. Gilby wouldn't be involved - nor would Adler. Adler is considered [by the rock community] as junkie/joke; that isn't my opinion [I don't know the guy, personally], but the opinion that the world holds -- in Jersey he is considered the weatherman. Adler was cool until he failed to realize that he was no longer relevant; he is a 'beggar' and a 'hanger on' - as touted by Slash.
In his mind, if tries to pretend like he's still 20, it will allow him to believe that there is still 'hope' that he will one day share the stage with his old buddies -- it's the only reason he isn't in a massive depression or a mental institute; the rest of the world knows that he just doesn't have the respect of the world or any of his previous band members!
Axl may be his friend, but he certainly knows 'better.' It's like an ex-girlfriend - you can be friends and not want to continue sleeping together.