It is probably due that guests frequently don’t know their travel dates so they search for a place with blank dates and filter out by pricing, neighborhood, etc. Some hosts took note of this and put their base price at maybe half of what they really charged. At first, this was just a very few subset of hosts but now there are plenty of them copying the same tricky strategy to gain exposure.
I’m in a position that if I do what others do then I will be as tricky as them but if not I will be left out of the game for the ones that look for a place without travel dates on the search. Seems that being honest doesn’t come with a prize here.