Development of in house players is not cheaper, that is a very illogical conclusion. First of all, all extremely high-rated hs recruits are being paid way more than their worth as they are being "developed" and secondly, it's completely illogical to believe that you are paying an in-house starter (or even 2-deep player) less than their Free Agency value once they become a starter or 2-deep player. If you're significantly under-paying a player making on-field contributions, they'll simply enter the Free Agent Market, realize their market-value there and leave. Firthermore, if you add up the average numbers listed, it is quite a bit less than what PSU probably paid their starting roster last year.
The trick is being successful is to realize "value" for what you are paying in-house or X-Fer FAs - i.e., they perform on your roster at a level that is equivalent to a market value higher than what you're paying them (if you pay them more in future seasons after that value is realized it's okay - but you can realize significant "value" in the Free Agent Marketplace if a Coaching Staff does their evaluations better than others (and Matt Campbell's reputation and trackrecord on this side of the equation is impressive).
But paying market value for elite hs recruits year after year such that your team is 100% "in-house" (and then paying them market-value of the Free Agent Market for your entire 2-deep roster once they have developed, if they develop) is in no way less expensive than acquiring an already developed "2-deep ready" player for an average price in the Free Agent Market - no way, because of the numbers. You're already paying your 2-Deep roster (some 50 players including STers) market equivalent sums, then you have to add all the $$$ you're paying to elite hs recruits, many of whom won't develop as you anticipated.... and some will be complete busts. No way are "in house" players cheaper - no way. They're cheaper in Pro leaues because they can't immediately go Free Agent once they sign a contract with that team, but that is not true here in the Prollegiate Minor-League NFL.