It's probably similar to the question of why commercial real estate is allowed to sit empty for years. If they lower the rent to attract tenants, suddenly the

It's probably similar to the question of why commercial real estate is allowed to sit empty for years. If they lower the rent to attract tenants, suddenly the building is "worth" less than it was. That makes it harder for the developer to borrow money using the building as collateral, and potentially triggers some awkward clauses in the terms of existing loans. In the case of the unsold Tesla inventory, marking to market would make the whole company worth less. Tesla stockholders expect the company to tell them a good story, and writing down the entire fleet of Incel Caminos would be a bad story.