If you really think that a vast majority of the young adults that are seriously in consideration for being drafted right out of high school (and, as i stated, that's something they'll know well before they declare for the draft) are seriously interested/motivated in spending 4 yrs in college to get a degree, then there's no point in having this conversation.
yes there will be some situations where the player is on the border and/or will take an ill-advised risk (which, as I said in my previous post, they'll have plenty of opportunities to get a sense of whether they are a serious candidate before they declare). But at least that's a choice he will be making and it'll be lot less frequent than you're making it out to be. I don't think it's any better to force a player to go to college for a year, risk injury, create perverse incentives in college, and potentially lose the opportunity to make a living from their talent just because the NBA can get a free year of evaluation and have people believe it's "Good for the player".
It's not like there's a history of littered stories of high schoolers declaring for the draft pre-2006 (though i'm sure it happened sometimes). Plus the system has improved since then.
The NBA has every right to do what it wants. But to pretend like it truly has the player's needs at heart (or even tangentially has the player's interests in sight) when there's so many counterfactuals around it makes it BS, imo.
Let's not even get into the wasted scholarships going to players that have no intention of completing their degrees.