The after high school hole

Unlike apprenticeships and such in various trades which can result in a very solid living for an individual, there really isn't anything dimilar for those who desire to continue playing after high school basketball and have the required degree of promise but don't meet four-year college academic requirements or aren't interested in furthering academic participation.

The push for some time now is for all seniors to go on to higher education (how about those costs lately?) because it's been quantified that college graduates as a whole earn more money over a lifetime and generally qualify for a higher percentage of jobs.

There's nothing wrong with that direction.

But why no basketball apprenticeships, if you will?

Sure, there is the option to go overseas and attempt to ply the trade plus various below-the-NBA level leagues here at home with rosters to fill but very, very few 17 or 18-year-olds are physically and mentally mature enough, let alone appropriately skilled, to succeed on that that path.

What's missing is a non-collegiate opportunity.

Now to answer the question posed, this is because there's no money to be made, no benefit to anyone setting up such.

The NBA certainly has no interest as it would be a hefty expenditure minus any guaranteed end of the rainbow pot of gold.

The AAU deals with talents prior to and through the summer after high school graduation but no further.

So a void remains.

Now abroad there appears to be various organizations in different countries dedicated to sports player development during high school and beyond, minus any academic requirements. Why is it happening there and not here?

Then there is also the stigmatization in this country directed to those young basketball talents who are not academically inclined, as if they are somehow inferior beings. Epithets along the lines of 'not being smart enough' or 'too lazy to work hard' are bantered about when there objectively is nothing wrong with a desire to focus on the pursuit of professional basketball employment. Plenty of high school baseball talents do just that, with a very high percentage falling short.

Granted, the odds are long for most and some realistically have zero chance of ever achieving the dream but it is also because the necessary infrastructure is absent in basketball. 

We don't look askance at those who slog or dog it through history and English literature because they see themselves as plumbers, electricians and the like. So why hoopsters?

Louis Barbash offers a very informative take, with a solid collection of background and history too.