So first the WWF/WCW Invasion PPV didn't live up to potential because a good amount of the WCW Stars weren't available due to the guaranteed contracts they were sitting out. Now with AEW Forbidden Door, it sells out instantly & gets the good initial buzz. As weeks progress, it's potential gets weakened by star injuries & unavailability from things like the AAA/CMLL dispute.
The only conclusion to make is these big crossover shows with the dream matches are cursed & promotions should stop trying them, right?
Don't forget SuperClash III.
The thing is you CAN pull it off, like New Japan did with the UWFI shows in the 90s, but that's because they owned both promotions and could decide all the finishes. Real people having to work together makes for much tougher booking decisions and never really works out well for anyone.