Which proves he is right. Your dirt bike ain’t gonna go 200K between rebuilds now is it?
Best it can probably do is 10K if you are very, very lucky.
Todays water cooled 4 stroke dirt bikes don’t last long with their itty bitty cam chains as well as the virtually non existence piston skirts and very small stemmed intake and exhaust valves, low tension rings and vapor deposition cylinder walls.
All great for performance and very light weight but no longevity.
It’s a two-stroke, actually. Still on original piston and rings from 1984. Few tens of hours, probably. Cast piston skirt might start to crack around 200 hours; so 200k — definitely not.