The Census Bubble had everything to do with the meltdown of 1990. It would be a mistake to include overgraded....and thus, overpriced...examples in any discussion of value over time. Overgrading has always been a problem, in any collectibles field, and cannot be factored into the discussion of real value gains or losses. Do not misunderstand: obviously, those who bought overgraded coins and comics have suffered real losses, but in an analysis of the relative health of a market, overgrading is not a legitimate factor.
In other words....that "MS65" you bought in 1983 for $1,000, that was really an AU50, cleaned, and is only worth $125 today, 35 years later, doesn't mean that the performance of actual MS65s are negatively impacted by such experiences. An actual MS65 today might be worth $20,000.
And I don't know about Barbers...I've been trying to put together low grade sets for years, and I just see prices going up, up, up. 1915 Phil 50c in 2000 was $20, now it's $150? And forget the keys. 1901-S 25c, you can't touch an example for less than four figures.