I don't think the stadium's impacted their finances that badly - they've been posting massive profits (not just revenues) the last few years, despite having a wage bill that's always been 30-60 million more than us (ie their model is to spend low on transfer fees but give even the youth big wages, while we're the opposite). It's more likely that certain of the shareholders have not been releasing the profits, which is why Wenger is so great for them - he's not inclined to spend big money in the first place, and his football is "attractive" so they can charge exorbitant ticket prices.
If Levy had hold of the profits they have, I'm certain we'd be investing much more of it into the team. The reason we haven't spent much of late is due to the way wages/bonuses have eaten into our revenues, as revenues haven't grown as fast as wages have (not Levy's fault - we went from mediocrity to competing in the big league now, and our rivals give even higher wages). Another issue is that prices have soared in recent years, even for youngsters (12m for the Ox, anyone? 18m+ for Jones....the days of 1m for Aaron Lennon are over) as agents desperately look for one last payday before FFP kicks in and as Emirates Marketing Project's spending drives up the prices for everyone who's half-decent.
Hopefully, once we start getting sponsors, competing in the CL, and finalizing our long-term manager, we'll have more funds and a stadium at a time when fees start becoming more reasonable again.
Arsenal have probably faced the same issues - not enough value in the market, funds or not. Or they may want to put faith in their youngsters, like Fergie (Cleverly, Pogba, etc). Difference is, United's old players are still class enough to bridge the transition. In fairness to them, they've missed Wheelchair all this season; we'd probably struggle without our most important player too, in Modric.
But only Wenger is to blame for the weak mentality his players have. I can't think of another team that constantly ends their season within one week. There was a great article in FT today about how critical psychology is to top-levels players, mainly about Fernando Torres but with insight from other players.
