A lot of bad takes in response to this. An actual reason is that if you are as productive for FAANG as the numbers imply, $1M+ in revenue per employee per year, then the value of having a barista make your coffee instead of you taking 10 minutes to do so is well worth the cost. It might cost the company 80$ of your productivity when you make a coffee but only 13$ to pay the barista. That delta over thousands of employees and hundreds of work days adds up.