For smaller companies yes leases can be broken but for others spending billions building college like campuses where they sublease space to businesses to sell to employees part of their worth is connected to real estate value. Others getting tax breaks by having people in an office in a downtown core.

For Faangs it's about power, control and real estate.

For the yc startup crowd it's often about investor control forcing it and fake signalling (come to my trendy office and look at people working) and inexperienced management who needs to see what effects their poor decisions are having with their eyes so they can pivot.