I don't really buy it to be honest. The situation under Wenger is way better than it would be if we were simply consistently midtable, if we became a Stoke or West Brom. It's a damn sight more interesting too. I'm fed up of life under Wenger, I have to make that clear. But occasionally finishing second like last year but always being in the top four, winning two FA Cups in the past three years, even being in the semi finals this season. This is a damn sight better and more exciting than being a boring midtable side who make no waves in any competition year in year out. We took an absolute pasting this year, and go out at the same stage of the CL every year, but especially as a fan who regularly attended matches up until this season, getting to see us play Barcelona or Bayern every year is exciting and you can throw in playing teams like PSG and Dortmund in the group stages too. That beats any excitement gained from watching an average midtable side imo.
If people give up on watching Arsenal now I'm highly sceptical that they'd stick around to be passionate fans if we were midtable or worse, I really am, because however unexciting things are now they could be a whole lot more boring. Mid table sides can chop and change managers as much as they like but that doesn't necessarily lead to improvements. Some sides just stay in mid table whoever is managing them, most sides never win the FA Cup regardless of who is managing them. If we became consistently midtable I doubt a managerial merry-go-round would be enough to keep people watching if it never lead to improvement, which is the scenario as I'm laying it out.
What happens if Wenger signs an extension, as perhaps looks likely, are you lot going to not bother watching Arsenal for the next few seasons? That's not an option for me, Arsenal is too big a part of my life for me to stop bothering because I want a new manager. I'm fed up of the relative monotony under Wenger, but fans stick with their side through thick and thin and things could be much shittier than they currently are under Wenger, and while this might be hard to imagine, other clubs are in shittier and far more monotonous and boring ruts than we currently are.