Case in point; Gumtree.

Free unlimited listings.

Filled with that much carp and unrealistic prices you can barely find anything worth buying.

In my collectables hobby, there's another site (won't mention the name lest I break a rule), which decided to differenciate itself by having unlimited listings.

It wasn't long and the ocean of identical 5c and 20c items made it impossible to find anything.

So now, they charge a final value fee plus a flagfall price on every item, in an effort to drain the swamp, as per popular modern parlance.