We've gotten top four for over fifteen years under Wenger while spending less on transfers than any other club.
Looking around the league, here's my thinking on who could achieve in line with that:
Probably: Ferguson
Possibly: Moyes
Never (not good enough): Rodgers, Clarke, Hughton, Jol, Allardyce, Pardew, Pulis, Martinez, McDermott, Adkins
Never (would need to spend heavily): Redknapp, Benitez, Mancini, O'Neill
Too soon or the jury's still out: Laudrup, Villas-Boas, Lambert
We know for a fact that many of the PL managers who've been around for a good while simply can't sustain a playing group without regular heavy spending.