@Bear; yes, I realize 4strokes are now doing the racing, and I do not even have a big problem with that, still close and good racing.
On the ecological front, you only need one 4stroke to blow it's guts out to equal a full season of 2stroke pollution. And go google how much oil is consumed by the 250 single 4strokes in one race, you would fall over backwards. It is actually more than the 2strokes used.
The 250 4strokes, in MX terms, have an incredibly short life-span. In Moto3 it is even worse, seeing that wide open throttle is used more often, which is when a moter is under full load and taking most strain.
And of course, it is not an "excuse" at all, just a fact. 4Strokes rev higher than 2strokes, with more moving parts and higher part inertia. 4Strokes are more fragile than 2strokes under even conditions.
Like you, I am also a 2stroke fan, and mourn their demise.