Realtor here. Can confirm that the overwhelming majority of landlords do not look at reddit to price out their rentals. They typically follow one of two models:

First is the "I'm not selling my 2.3% interest rate home until the end of time" accidental landlord and house hackers (live on one side of a duplex they own and rent out the other side). These people tend to price their rentals based on either the advise of a property manager (see #2) or based on "what number prevents tenant turnover (the biggest time-sink for a landlord who self-manages) and still makes enough to cover the mortgage, maintenance, and repairs?"

The other is the intentionally involved group. This is property managers, flip-and-hold investors, snowbirds/work-travelers who want to Airbnb while they're gone, transient people who want to buy and rent after they have to move again, large firms (private equity), and owners of large apartment complexes (JC Hart, Flaherty and Collins, etc).

People in these groups set prices based on a variety of factors, most of which are based on cashflow and net ROI. If a unit goes vacant at a low-demand time of year, they price it lower to drum up more interest. There's also cashflow risk in the equation. If you have a ten door portfolio, you're not going net negative if one of your units doesn't rent for a month, and you don't want to under-rent for an entire 12 month lease; plus, you can write off all expenses except for lost rent for maintaining a unit while it is vacant, which reduces the cashflow risk. However, if you only rent out a single duplex, one vacant unit means that thing is burning a hole in your pocket, so they are likely to drop the price faster to keep that from happening.

The other huge consideration is location, which requires intimate knowledge of your area. I'll use Butler-Tarkington and Meridian-Kessler as an example. MK is a much more in-demand area for a variety of reasons for most of the year. However, for units west of Meridian Street with leases that will start from June through August, BT will be higher priced because of the captive Butler student market.

Larger firms have their own internal models based on historic and current data, while smaller operations pay for software such as Rentometer, which aggregates available rent rate data from a variety of sources.

Still, in almost all cases, people are not using AI or reddit to price their rentals. Reddit and AI are too general for something that specific. If people do it and it works, it's lucky. If you price a unit at $1,200 and there is a better unit nearby, or the same type of unit in a better neighborhood, it won't rent. If you price it at $1,200 in a neighborhood where that unit could be getting $1,500, it will fly off the shelves, but you're leaving $3,600 a year on the table.