EXACTLY! Show me any track any day, a rider who hasn't spent a wad on aftermarket parts for his 250F or 450F... Here's where I love to compare, 2 strokes are cheaper to put parts on as well. I have my 2006 CR125. I have put in a new crank, CR250 Forks, new piston, new wheels and tires and countless other things on it. It is better than new and have less than $2000 in it total. I will be putting about $600 or so in it soon though for a 144 kit. But either way, I'll compare anyone's bike against mine. Even a brand new one. CR500AF, same thing. $2,000 in it. Now of course, most people can't do the 500 thingy. But the 125, most can rebuild a 2 stroke motor. I bought it for $1,000 and then put on the parts. Someone didn't think they needed an aircleaner...
Also, I'd like to point out that many of the new 4 stroke buyers have loans out on them, so the cost is even higher than they say.