Indeed, new strings every gig, or every other gig or so is the normal at that level.
Of course, at that level they may be earning 10 or 15 grand a night for playing a large venue, so can afford it. Or they may even have sponsorship deals with string manufacturers.
For mortals like myself its a case of finding a sting that sounds consistent for longest. Not necessarily new or bright, but decent enough once played in and then consistently maintaining that for a long period.