No it's long because people buy it and then asks for a lot of recommendations. There's really no way to spin this any other way.
For example, the T1 thread is nowhere near as long as the HD800 thread (still on the first and only thread), and the T1 is as old as the HD800 and is also one of the TOTL at that time that is considered on equal level. Then there are other "classics" like K701/HD650/DT880 the used to be the the "top of the game" but again, nowhere near the long discussions on how to get the best out of it unlike the HD800. Asking for synergy pairing always means that you think your gear has untapped potential, which means you aren't fully satisfied as how it is now. So in that respect, I think it is completely fair to say that people searching for the best synergy for their HD800 (and yes, this does apply to all headphones as well) - whether it is in DACs, amps or cables - cannot be said to be satisfied with their headphones as they are. The fact remains though that there's such a HUGE thread for it that greatly out numbers any other headphone on this forum, must point to that when people buy the HD800, deep down they really may not be that satisfied with how it is out of box.