"Actually your argument would support the opinion that minor leaguers are OVERPAID! Since the supply far outruns demand."
No, the supply does not outrun the demand. There is no limit to the number of amateurs an organization may sign. The organizations don't sign more because the organizations don't view the available supply as matching up to the skills required (you can debate whether the organizations experts don't know their jobs and misjudge some amateurs potential - but that is a case by case and not a broad proposition).
There are millions of people who are willing to work as top level coders for six figures; there are several thousand who actually have the necessary skills. When we speak about supply, we are speaking implicitly about those that industry deems as its available supply (in other words, to be considered "supply" you need to first have the needed skills).
"Even if it's doing $80 an hour lessons at the local academy."
Yes, lessons are expensive and, yes, I was one of those obsessed parents. But, I hope my kid is earning more than a part-time $80/hr when he is in his peak earning years. And a note to parents paying for lessons: just because you were a pro player DOES NOT make you able to teach. Make sure you are getting an instructor who knows and understands their trade.
There is definitely a difference in potential in players - and that is often expressed by the round a player was chosen (recognizing that economics and other factors may also be present). No question that the players drafted in top rounds have been tagged as having greater potential or a higher ceiling, but to blithely conclude that teams draft "companion ponies" is result oriented reasoning. Once in proball, all players have the chance to develop their tools, and while top picks generally are given more chances to fail, every player has a legit shot. Organizations WANT every player to move up - if not in that organization then as part of a trade to another team.
Yes, players in the low minors are replaceable - BY OTHER MILB PLAYERS (and once a year by the top college and HS players - though mostly in SS and low A). If it is implied that an organization could throw a dart at a list of all college players and replace a current player, I think that is not correct. If that replacement player was rated as having the potential, that player would already be signed.
Players are indeed fungible - but only with other players who have been rated by experts within that organization as having MLB potential (which most will never each, btw). The players are not fungible with players who WANT (or hope) to play - a player's hopes, wishes, dreams, or prayers are irrelevant.
I don't believe life in fundamentally unfair. By preparation - in baseball by working hard, in academics by working hard, in a job by working hard - each can achieve his potential. Not everyone has the same potential, but each can work towards achieving his potential. I have found that generally, life does depend to a certain degree on timing, but I have also found that in many circumstances I can be prepared to be ready when that time comes through hard work and planning. (I am a half full glass type.)
All this having been said, the minors aren't going to harm a college kids maturity and growth into his ultimate self (I don't feel the same about HS kids) regardless of the salary; and I believe the opposite is true; that any kid who has the chance will come out better prepared for life.
I just wonder what is so unique about the INDUSTRY of baseball which makes it so immune to concerns about the conditions its employees labor under?