What is the logic behind selling at such a steep discount? Lack of buyers or trust? Seems insane to sell tham at -50% or more, especially since you can use them yourself (if you're a startup)

Risk-reward calculus. A buyer may not take the risk or hassle of going underground only for a small upside. Basically it is not as tempting at 90% of list price, but it is at 10% .