The service academies will never be closed, nor will they be significantly restructured; they are too deeply ingrained in American culture for that to happen. Movies, novels, Army-Navy football games, etc, all have insured that they will go on as they have gone on. The only thing that might change that is if the US were to suffer a disastrous defeat in a really big war.

But it is still an interesting question to discuss.

One thing I have read in the past is that both the academies and ROTC share a weakness. That is, they try to gauge gauge military leadership ability on the basis of an 18 year old's track record, or they figure they can teach it. That seems a chancy thing to do.

Perhaps a better thing would be to have potential officers serve in the ranks and thereby see if they have some potential. If they do, they go on to what ever officer training program you care to create. If they don't, they serve out their term and go about their lives. I think the Germans did something like this in WWII.