It’s one thing to build a house and sell it, it’s another to build it for the sole purpose of renting it at peak market rate.
Corporations use to build company towns and rented them at higher rates than they paid the workers.
People fought to stop this but there are always people who insist on relearning these lessons the hard way.
These articles are speculative on the cause. I don’t see any data on the supply increases.
Some of these cities, didn’t increase supply. For example San Francisco saw similar decreases it they offer to exploration there.
The rents decreases are year over year but are flat over a two or three period of time, it’s just as likely the rent increases were a bubble that popped and not because of some unspecified change in supply.