He became manager of an almost bankrupt club half way through the 1999-2000 season when we were stuck deep in relegation trouble. He worked off a shoestring budget for the next 5 years or so, and yet still got us to two cup semi finals and a play off final, as well as being in contention for the play off places in three other seasons (2000-1, 2003-4 and 2004-5). When finally given money of any significant amount he got us promoted immediately.
The same has happened at QPR. When given any significant amount of money to spend he got them promoted.
If Warnock had had the support that Robson got, we would not have been sliding match by match towards the relegation places. We will never know (because he wasn't given the chance), but I believe we would have gone straight back up in an automatic spot.