The reason you start on a small bike is the learning curve is easier...
Buy a 1000 ride it for a year, while another dude starts on a 250/500. Then put that 250/500 rider on a 1000 after a year and Ill bet 10 to 1 he'll ride circles around you! Why might you ask? Beacuse your fighting with that 1000 to control it, PROPERLY!
Make a mistake and blip the throttle on a small bike most likely you'll just snap you neck back a bit, do the same thing on a 1000 and your looking up @ the sun while flat on your back....
And for the guy whos friend own the rebuild shop its guys like YOU that keep him in business.. Another squid on a bike that cant ride, because his balls are bigger then his brains!
FYI, Ive had 4 bikes, a POS Honda 250 (learner bike), 2002 R6 rebuilt (till this day the bike I had the most fun on), 2004 GSXR1000 (when I thought I was fast), 2006 cbr1000 (when I realized fast in NOT a straight line)