My point is that for these purposes, users are not fungible. You can't just divide the cost-revenue equation by the amount of users N on both sides.
No it's not.
If you add a pile of fictious users to the usercount, the apparent average cost-per-user drops as the fictious users do not use the service and do not add their own costs. This lowers the apparent amount of per-user revenue you need.
However, as fictious users also do not generate revenue, this is all smoke and mirrors.