How much difference is there between a bike from 2000 compared to 2010?
Depends on what you count as difference, and what type of bike. I think there have been big changes in all mountain/trail bikes, but ones with more specific uses are much the same.
I’ve got a 2001 santa cruz superlight, 9 years on, the latest frame is a bit stiffer, and you can get stiffer forks, cranks and a slightly slicker gear change, but apart from that, the same bike with 10 years newer technology will still give pretty much identical performance for its intended task.
Ditto a SS inbred.
When compared to bikes from 1990 and 2000?