Or, Say I own and house, and I want to rent it out. I would calculate how much I would have to charge for rent for it to be worthwhile to me. Why would I care what anyone else is charging?
Then you probably shouldn't be participating in this discussion.
But, if the price you calculate this way is too large, no one will rent your house.
And, if the price you set this way is too low, you're leaving money on the table, which you may or may not be fine with. If the difference is high enough, someone might even pay you the rent you asked for, but then rent it out themselves to someone else for the higher price, and pocket the difference, which you may feel cheated by.
If you just charge what you need to cover costs you may find yourself with a vacant apartment.
I added /s because dear lord this thread is full of people who think its true. Housing shouldnt be an investment venue when we have millions unhoused.
You want to make more money in housing? Build more housing.