[jlokier]

I think it's sometimes because they see the value of future higher rent after a void is worth more, in straight up cash value, than accepting lower rent with a long term commitment.

I've seen it for years: Empty shop buildings, a glut of local businesses wanting to rent them, but they are kept empty until some chain willing to pay double turns up a year later. For the landlord, it's worth waiting if that will be the outcome.