Fast is a questionable word... Turn the clock back 100 years ago, and going 40-45 mph on a Ford Model T was extremely fast for the people back then. As time goes by, and technology advances, we become capable of going even faster. That is why the fastest production bikes being made (S1000RR, Busa, 2011 ZX10 minus the recall) are not fast enough for some folks. When I first got my Z06, I thought it was extremely fast stock and was perfectly happy, but after a while you get used to it and want more power, then comes the mods (turbo, nos, etc..). Then once you mod it till you can't do any more, you sell it. It's a vicious cycle.
I'm sure blue angel air force pilots laugh at the most modded turbo nitrous bikes out there. It's their raptor jets that are the definition of true speed.
And who knows... perhaps 20-30 years from now there will be an aircraft that will make the F/A 22 raptor seem slow and inferior.