We spent up big under Emery as well, we just wasted the spending. That's not something you can lay at Arteta's doorstep, though his snobbery about working with Pépé, Saliba et al. is a grievance.
The fact the players we're signing and developing are playing and performing is a big upside of the changed approach from the whole leadership, despite the squad gaps and the debate over White etc. Their youth is also good and means they'll probably outlast Arteta.
As for more spending, the blatant need for a midfield and forward signing is there. Taking up a plaintive position on that need as if it's specifically Arteta's fault is also unclear. To succeed that investment is necessary, and the coaches of rivals receiving praise demand it.
To put it another way, thinking we have to succeed with lower spending than other clubs is the sort of loser thinking that's held us back from major honours for getting up towards two decades.
If Conte were here he'd flip his coiffure and come out in the press calling us a midtable club after every loss—just as he does at Spurs.
My suspicion is that the decision to rebuild the squad from the backline was driven by thinking about player turnover. Speaking of which, it's been printed in a few places last couple of days that we've turned down a Marseille approach for Saliba and he'll return to Arsenal in summer.