It's just such a personal decision, it's impossible to quantify because each person will weigh each variable differently.
Its a decision which chooses one path and burns the other path - sure, you can go to college at any age (I did as an older student), but going to play baseball in college is not possible. And college baseball is likely the last time a kid will play for a team he will care about for the rest of his life.
Most of my son's peers who were drafted out of HS didn't make MLB (7 - 9 years now), some are still chasing the dream, most are done. Of those done, most have tried to go to school; none so far have graduated; one kid actually got his degree while his was playing.
But, I don't know if the decision can be boiled down to economics. Having gone through the decision once, in hindsight trying to come up with an economic rationale was not the right approach (though that was how we rationalized the - correct for us - decision). I don't know what is - probably because the decision is so personal and individual - but its somewhat analogous to a decision of high academic or baseball power school. You are giving up a lot, to gain what IMO, isn't very much of a head start.
In college, injuries cut players potential short more often then bad coaching. Bad coaching or a low visibility program may impact draft round, but if a kid has the chops, he will be found and advance in proball. In the overwhelming majority of cases, if a kid isn't pro material out of college, the kid really wasn't pro material out of HS.
(Continuing my unabashed promotion of the Ivy schools and Stanford [d1 only talking], graduates do actually go to Goldman and its peers on a regular basis.)