I don't think anybody is knocking Fletcher for getting 80's, that in it's self is decent enough, but it is important that batsmen do get centuries. If your not scoring them at FC level, then how will you score them at Test level. I also don't think 30's and 40's (Powell) are worthy to be selected to the WI team (even if it is Zimbabwe), and it is enough to replace those in the team? Only thing you are going by is his age? If he was making 80's consistently, then I would probably tend to agree with you. I would say in time he will get a run. Just not yet.
I don't think anybody really rates Travis Dowlin that much, he is somebody who has made the most of his ability, which isn't a great deal (FC average of 30 FFS), and is only getting a game because of the scores of injuries in the WI team. I have never though of Runako Morton that much, except that he is a nut case of the highest order, and again injuries is the reason he is picked. I mean he is solid as WI domestic FC batsmen go, but he is gash at Test level. If guys like Darren Bravo and Kraigg Braithwaite can step up then I don't see how Dowlin or Morton should ever get a game again, barring a massive injury crisis.
To me if you want to replace these 'clowns' (your words not mine), and replace them with younger players, fine, but they have to have very strong performances to replace them, other then then their ages (under 20) and their potential. If you are going to replace the mediocrity, then you shouldn't just replace them with youngsters who are not ready nor good enough. Perhaps they will be, give them time.
Anyway I doubt you will agree, as you haven't already, so that my say on the matter.
On a different topic, this Veerasammy Permaul lad from Guyana looks a solid performer at FC and List A level. At nothing else he is very accurate.