Sure, they aren't nearly as popular here, but their popularity gives them a prestige that necessitates both star treatment and a considerable sum of money to make coming to another country worth their time. While they wouldn't get the millions they are making for the Manchester gigs and inevitable festivals (rumored to be headlining V), it would still be a large chunk of change. So they'd be on the main stage and the second or third name name down and have a modest crowd while the derps are in the Sahara, the beer gardens, or at the Outdoor watching some trendy indie synth band.
Can Pulp really be as popular in Slovakia and Australia as they are at home? No, yet they were the #1 or #2 act of every festival they played this year. Same deal if they came here. Acts like The Stone Roses or Pulp may not be the band that nearly everyone wants to check out, but they would be a much higher priority and deal maker for a small but considerable base of fans, and continue Coachella's prestige as the festival that brings in some acts that can't be seen at all the other fests.