The average cost of an American gubernatorial election has never been as low as the proposed funding levels for the 2010 election. The average amounts for an open-seat race are even higher.
Looking at the pattern of races where there’s an incumbent victory, most (the non-competitive races) are below the average, with a very few (the competitive races) above it. Races where the incumbent lost are, by definition, competitive, and incumbent losses below the “pink line” average are exceedingly rare. Ultimately, it looks like the Democrats would have been doomed in 2006 from an inability to reach the public regardless of who the candidate was.
(Data from the excellent Gubernatorial Campaign Expenditures Database hosted by UNC and compiled by USC.)