A business is stuck paying for that lease regardless of how many butts are in seats in it. That is a fixed sunk cost they can't do anything about.

However, every employee not in the office isn't using office pens, putting wear on office furniture that will need replacement, filling office trash cans that need to be emptied by someone, burning out office light fixtures that need to be replaced, and using office toilet paper that will need replenishment.

Bringing them back to the office doesn't make the lease any cheaper, but it does make operating the space more expensive.