There is usually one of two factors in sides going to the Premiership and being successful: continuity/consistency or serious investment. I know this is very simplistic but I hope it illustrates a point.
Continuity:
West Brom, Swansea, Reading, Wigan, Norwich - all of whom have picked a philosophy and have stuck to it; in the case of West Brom and Reading that has stayed the case even after relegation.
Investment:
Stoke, QPR, Blackburn, Bolton, Middlesbrough, Fulham, Ipswich,
Stuck in the middle (neither)
Charlton, United, Watford, Wolves, Birmingham C
Borderline:
Southampton
The obvious point to me is that the sides who have stuck with a philosophy of investing in younger players at lower transfer fees while generating an ethos of hard work have not only generally been more successful but they've also found it easier to adjust when relegated. Obviously Wigan may prove an exception to that rule.
Investment seems to me to be a much riskier strategy and the pain on relegation is much worse. However, the worst strategy of all is to not really have one (see United's January spending in 2007) and that is what has cost us since then.
We HAVE to embark on a policy similar to Reading, Swansea and (to a lesser extent) Southampton: bringing through players from our academy and supplementing them with cheaper, younger players from the lower leagues or abroad as McCabe doesn't have the funding to do what Peter Coates has over the past 5 years.
Incidentally, quite how Tony Pulis' job is so secure is beyond me given the money they've spent over the last 5 years - one FA Cup final for £75m does not represent great value in my eyes.