These types of platform can only work if there is a healthy portion of users that provide services and a decent portion of users who want those services.
As such, how do you launch such a platform with zero/little users?
You could acquire the service providers prior to launching (e.g.: via a pre-lease sign up page and a marketing campaign to go alongside) but that has its own issues: for starters, no-one will have any reviews, and from a technical perspective you'd have to implement a way for those users to complete their profiles before launch.
I have seen suggestions of faking a user base, but that does not sound appealing to me and I am not sure of its legality.
Also note that most marketplaces take a relatively long time to really get going. For example, Etsy has been going for 14 years.