If there's no competition for second hand sales even with this procedure, shit is going to be worthless
Say Gamestop buys in
You buy your $70 BF4, play it, get tired 1-2 months in return it to GS and they offer only $25-$30 for tops
They turn around sell it for say $60-$65 "Pre-Owned"
So MS and Pub get a cut from your resell say $5-$10, then when that new used copy sells get another $10-$20
They just made close to $100 off one copy of BF4, repeat
This may look great, but if there is no competition from other retailers, Gamestop can force any TIV (trade-in-value) MS/Pub asks it to be
Pub knows people are trading in their shitacular title and ask MS to force the resell to be $10-$20, even though title is less than a month old and still selling $70 new
Forcing GS to lower it and any other retailers using the program/service
GS had competition in the form of Best Buy and their 100% Trade-In's, really started eating into GS monopoly/cash cow, GS challenged and rose TIV's across the board, started adding those same deals with twist that still benefited them
So MS + Pubs + GS/Retailers that want to get in on this will literally hold hostage the market, the users will be at the mercy of their prices
There's a reason second hand sales have checks and balances, and so many avenues to sell your item, competition breeds good prices, deals, etc.
Collusion on the other hand will stagnant the market, less purchases, might even detract newer purchases