i would partially agree with you, but regarding pollution,if the auto lube would tune properly then one can see very little amount of smoke out of it,rather what you say about a miss tune carb of 4stroke bike,nobody bother that how much pollution that would produce,coz thats un seen pollution......
and regarding plugs issues i would say only, if you ever take a look of a plug of a yamaha rx115 then it always came out red as like 4stroke bike,s plug....and i used to change the plug after every 6 months(approx)...thanks