I get what you are saying but how has he built a great club in Arsenal? you're an average club who has always been one of the biggest in England (Herbert Chapman did more for Arsenal than Wenger), he has if anything restored you to a position you were already in the late 80's for example and you have fallen backwards as a club now which will need a major rebuild.
It is hardly a job like Shankley did with Liverpool, creating an international global phenomenon and a european powerhouse, one of the iconic clubs in football or what Fergie did with United building up a team from scratch.
For me that is an Arsenal fans way of ensuring Wenger is remembered as a great but from a neutral perspective, whilst I respect how long he's stayed in his job and the length of service he's give the club, he still doesn't deserve to be known in the upper echelon of managers. It is another case of longevity substituting for actual quality.
In the UK, he will of course be remembered as one of the great managers. He's one of the best British team managers ever (in top 10 for sure).. but internationally, it is a different kettle of fish.
Big ears alone doesn't equate to greatness, no one is silly enough to base it on that achievement alone and guys like Di Matteo's are anamolies, but it is definitely a huge factor in separating average from great, as is consistency over a long period and league/cup wins etc. It all gets taken into context.
I get what you are saying as well, but I think you are missing some context.
First Chapman has to be tempered with giving Sir Henry Norris a lion's share of credit. Without his money (we were called the Bank of England team then) and his shadiness (briding Arsenal way to promotion to the Premiership) Chapman never would have happened. And ironically it wasn't even Chapman who actually thought of the WM innovation, it was one of his players. So Chapman is a bit overrated historically IMO. Never fancied the WM anyway.
Now you have to fast forward to 1990s. Graham was the one who built the modern foundation, winning the league in historic fashion in 89 then 91 and even bringing the only respectable European trophy we ever won - Cup Winners Cup in 94. But you have to also look at the serious damage done by Graham's mistakes. After his famous bung scandal and its fallout, we had Bruce Rioch and finished 94/95 on
12th spot. This was after a few years of Graham going off a bit dictator and completely alienating many of our flair players (Thomas, Davis, Smith, Limpar). David Dein has to get credit too, but when Wenger first arrived at Arsenal there was absolutely no indication that Arsenal were on the way up. We very easily could have fallen even further down the table at that point and never recovered. c.1995 Blackburn and Newcastle looked like far better bets to challenge United and build on their status.
Also, this is about the only time I will bring money into it but without Wenger, there would have been no Emirates. See, our board made some really bad strategic decisions after the Hillsborough induced stadium retrofits. While you made some astute choices in the hospitality market, Arsenal completely missed the board in 90-91 with the Highbury remodels that left Arsenal very weak in match day revenue in the 1990s. The improvements Wenger made on the pitch leading to the 98 double had a massive effect on Arsenal's finances. Another year or two of Rioch or similar 95-97 and we never would have been challenging your United in that 98-06 time frame. We would have been mid table and probably lost Bergkamp not long after. Also can't underestimate how much the 98-04 era grew our global fanbase. We would have nowhere near the number of world wide fans without that. Again, our global fanbase would probably be Blackburn size.
The modern approach Wenger brought to the club is credited with not just revitalizing and modernizing the team. He brought about the end to the drinking culture that still dominated Arsenal in the mid-1990s before matches and Tony Adams credit those modernizing changes with changing his entire life for the better. His scouting network that brought in the French and French-African players was a coup for English football and really began the trend of the PL clubs looking all around the world for players not just to Dutch and Scandinavian players. These are two massive, massive changes that layed the foundation for Arsenal reaching the status it did. Without these changes we would be where Newcastle or Blackburn are right now at best.
Is Wenger the only manager that could have modernized Arsenal and paved the foundation 97-06? Maybe not. But he was the one who did it. I will be the first criticize Wenger's mistakes of the last 10 years but you are definitely greatly underestimating the massive impact he has had on Arsenal.