That's one of the great misconceptions of our fanbase.
For starters, Kiffin (and particularly his staff) was not cheap. If anything, Kiffin's staff was wildly overpaid. Kiffin's personal salary was not eye-popping, but if memory serves his staff pool was 4th in the SEC, behind only Saban, Richt, and Urban. Monte was making well over $1m/year, which was basically unheard of for assistants at that time. Even today, those kinds of assistant salaries are more common but still are very large.
The hires that followed were cheap not by design, but because cheap choices were the only ones. I think that's a popular argument around VN because it makes us feel better. "The only problem is that we're cheap. All it takes is opening up the wallet and we'd be great again."
The last decade of Tennessee football has been a black hole because of administrative dysfunction and incompetence. There is not a lack of desire to spend money or a lack of desire to be a top program. The problem is that there are factions of people (one in particular) who want to be good on their terms. They want to be great, but they want that greatness to come because it was their idea and they want to get all the credit for it. It's an ego thing.