I still reckon the the change from FS 9 to FSX was much more drastic than the change from any of the previous versions which I have installed and run......!
I agree.. but also note that there was an extra year in there too. FS2002 - FS2004 was a two year gap. FS2004 - FSX was more than three years and will likely be the current FSversion for at least three years.
Don't be surprised if by 2011 curved, monitors that wrap to nearly side-views are common-place and quad-core 5ghz, 10GB, DX13 computers are the gaming standard.. lol