I think 4 strokes are going to end up being 80% engines (run them at 80% WOT
80% of the time for long life). It is simply the number of moving parts you are
dealing with.
I know small 2 strokes will run WOT all the time, I suppose they are designed
that way but you don't hae that many moving parts. We have guys here with 20'
pontoon boats and decades old ~20hp motors who use the throttle like a switch.