Bad cobalts won’t have much value until the trade in system gets fixed. That said, some people will still buy them once they get cheap enough – it’s a cool skin and loadouts don’t make that big of a difference. Also, bad silvers/gold will have value due to trade ups. Spending $3 on bad silvers or $8 on bad golds will be a better deal than buying elite cases in many instances – trading up for a guaranteed gold/cobalt for your merc of choice is a better deal than hoping for a lucky card from an elite case.
For that matter, spending a dollar on a bad bronze and trading up is a better deal than an elite case if you are looking for a silver. Sure, leads/irons won’t go for much since you can buy your bronze loadout of choice for $3.50. Everything above there will have some value, though.
I guess it’s possible that everyone will be putting them up for sale and supply will outstrip demand. At that point, the cost of high level cards will drop a lot across the board and no one will pick up elite cases. That said, if getting high level cards was that easy, people wouldn’t bother buying elite cases. There can’t be that many bad high level cards out there, and they disappear as people trade up for higher level cards, so the price shouldn’t crash too drastically.