> The cost savings of work from home must have been enormous for these companies, yet none of that savings or record profits trickled down to the people writing code

Lots of companies had long term leases or obligations anyway. Eventually the 'cost savings' were probably there, but I don't know too many companies that were just able to jettison their initial lease payments in the first few months of the pandemic. I know I couldn't quickly get out of my office lease.