...it sounds like you're complaining about the people who are trying to make money from a relationship being the ones to put the work in. If you're renting or selling, it's up to you to put in the legwork.
Some people view that relationship as "you need me so come to me" - in my experience, those are the worst people to live with.
I rather like that Facebook lets people act naturally. The people that reply to those lazy posts are usually poor planners desperately seeking a flatmate... so neither group engages with my ads :D