Sooner or later, they're going to have to spend. With all Wenger's faults, you cannot deny that with the resources he's had, with the players at his disposal and the net money spent, its quite an achievement that he's still among the top four every season. However, the first thing that needs to change is our wage structure, we do not pay top players enough money tbh, inevitably they end up leaving.
If Wenger leaves by the end of next season, he'll leave behind him such a limited, uninspiring team that i really pity whomever comes after him. Unless the club spends big in the summer and brings in 3-4 top quality players. Even then I don't think it would be enough to win the league though, as we have terrible depth. However at least we stand a chance in cup trophies then imo.
Would not be enough. Are Fellaini and Rooney any upgrade over recent departures such as RVP and Cesc? I don't think so.
That being said; it would be a massive upgrade over the current extremely mediocre team.
The club recently announced that they were releasing Arshavin, Denilson and Squillachi. Long overdue, they should have done that ages ago. Now we need to get rid of the likes of Diaby, Bendter and co. The mere existence of such players in the club is a sign of lack of ambition.