That is a good point. The people who invested in long term leases in the late 90s in malls went bankrupt but the malls mostly stayed around. I assume the same thing will happen with office space. Demolishing the building is expensive, might as well keep the lights on and wait to see if someone wants the space for offices or storage or whatever.
Musk is doing this now by holding up a refinancing of Twitter’s building by defaulting on the rent. Anyone with a big enough war chest can just stop paying, drag it out in court, and wait the owners out. And tech companies have some of the biggest war chests.