I know about this, but there is some facts. When any client knock you and they don't make order It's down your gig's value. And It's true the appropriate budget buyers if we work we enjoy and the quality of work always possible to do best.
Other thing is people never share first what's their budget. As a seller or buyer both term i hope you know. 99% clients knock some sellers and they talk about there needs then ask to sellers for price range. There is also some part that, most of time the client’s not even reply after hear the price from seller. We do knock for update then few days later sometimes they share that they found someone in a lower price. So they can simply tell us without avoiding. Or they can share first what is there budget limitations, i know it is not possible to say bcz if client gets a lower budget seller that is thier benefit.
Fiverr simply can set up for a service in a category what should be the minimum price. In people per hour you can see this function so it keeps both side balance for a market place.