Tenants are a pain in the ass. Buildout (for which tenants often expect you to pay) is expensive. Unless you're leveraged to the hilt, you can afford a few quarters of loan payments on an already-built building. That being the case, signing up a marginal tenant is throwing good money after bad.

If the market has changed in permanent ways, and you're never going to see another good tenant, you want to learn that as soon as you can, and then get out. This is why our great leader always structured his deals so the company could declare bankruptcy and he could skate away with the previous profits.