I like this topic.
I do think 4stroke will be around in the near future, it will pick up slowly and of course there will be many flaws at first.
I raced mx in the era where 4stroke took over the 125 and 250. At first there were only a few guys who ran them locally and they were quite a bit heavier but they had more torque, no oil to mix with gas, etc. The downfall was that if they stalled, they were a pain in the rear to start up again! The major companies took a few years to conquer it and BAM 4stroke took over the mx world pretty darn fast. (now 2 stroke is almost non existant in the 250 and 450 class)
Will this happen to RC? I can see where people would say yes and I can see where they'd say no. But yes I do think there will be a competitive 4-stroke motor out within a few years