Who pays the broker is generally a sign of the market conditions. When it's a renters market the landlord eats the fees, when vacancies are down, like now, it's the other way around.
Also, for all the reasons mentioned in potatolicious's other post [1], it's difficult for a landlord that is renting directly (i.e. without a fee) to convincingly communicate that fact to potential renters.
[1] https://news.ycombinator.com/item?id=6027785
