I hope that Fiveer realizes that Businesses evolve and change and with that also most of the time the Branding of the person/company, and not to being able to change a Username I think is a bad design decision, If Fiverr is afraid of too often changes then just allow it every few months and notify all past customers that the name has changed, I don’t see any problem with this. The only static thing of us should be our ID in the Fiverr Database and not our Usernames.