Yes, we did win titles before Wenger but not since the 30s had we had such concentrated period of success.
3 titles, 2 of which were complimented by the FA Cup to make them Doubles. One league season unbeaten. A couple of other FA Cups. And all in a style of football which no-one expected Arsenal to be playing. In the 90's you couldn't say "Arsenal" without the words "boring boring" preceding them. There's some dispute about who brought Bergkamp to the club, there's no dispute about Henry though and all the other players he brought in in that era. I'm not even going to list them, you know who I'm talking about.
So yeah, what have we achieved?
What have the Romans ever done for us...
And yeah, there were missed opportunities but I'd suggest you could say that about any club in any era.