The club has failed to make the necessary adjustments after losing players in the past. Back in 2005, we started the season and played until Christmas without a squad good enough to finish 4th, and went into the final game of the season without CL qualification in our own hands.
Likewise, last season, we started the season without a squad good enough to finish 4th, though this time made the adjustments a day or two before deadline day, after we'd all had a vision of an Arsenal so weak that they'd have been roundabout mid-table. Still, despite having van Persie, we had an absolutely atrocious midfield that more or less depended on the presence of one player. And had van Persie got injured for a month or so at any point, does anyone really think we'd have finished top 4? The guy played all 38 league games this season. Forget scoring all those goals, that's the most implausible stat of the lot!
And the fact that we usually manage to scrape into the Champions League is not much of a platitude to those who still harbour an ambition that Arsenal might actually win the thing again one day (it ain't immoral to be champions, after all). The most important question is not how to qualify for the CL, for most of us anyway, it's what moves could Arsenal (not some other club with a different approach) make this summer to get themselves into the mix for the title next season. Keeping van Persie is the biggest part of that, IMO.
For me, the departure of van Persie is not something of the sort of magnitude we've encountered too many times before. We've had our best players leave in the past, and some very good ones on top, but only really Cesc has been as pivotal to our side upon his departure, and I don't think many would argue that we've become a better team, and especially not a better unit in the middle without him.
What would happen if we lost van Persie next season? For me, there's a simple question of where the goals would come from. Can we trust the existing crowd to combine for an extra. 40-odd goals next season (just in the league) with Podolski's help? Personally, I don't. Even if we made our usual 2nd-tier signing from L1, this squad will end up weaker than it was before, because that's exactly the way we operate.
Anyway, all this is moot, because it's pretty obvious he's gone. If he wanted to stay, and there was anything we could say to convince him, we'd have got it done before the Euros. I'm not looking forward to his empty platitudes about being a gooner at heart, and thanking the club for all they've done. He can fuck off like all the rest.