The problem with Arsene is that what worked in the 00's didn't work in the 10's .... sadly Arsene never got that ....
The days when you could buy / develop / find two or three top class players and win the league .... gone ...
You now need not just a few, not even eleven, but a squad of twenty five very good players to have any chance ....
Same goes for tactics .... just because something worked in 2004 doesn't mean it will work today .... whatever you're good at now come next week the opposition will have adapted .... even the worst EPL team today is a million miles ahead of the best team twenty years ago .... maybe not in ability, but in diet, fitness, coaching, medical, mental .... the list goes on
Arsene was great, fantastic, the best ever .... but he stayed a decade to long and left us a long way behind our rivals ....
There's a reason managers have a 'best before' date ... doing the same thing over and over, in the end whatever competitive business you are in you will always be overtaken .... happened to Utd and it's happened to us ....