It's about rock music being played in arenas, he thinks no-one did it better than Dire Straits:
Despite being made up of the most normal-looking musicians in the world, Dire Straits always knew how to get the job done strictly with their music. There were a few moments where songs would blend in with each other, but what Mark Knopfler was doing with the sound of the band every time he played had more to do with his natural musicianship rather than worrying about some studio tampering.
Since the music did most of the heavy lifting, Plant felt that Dire Straits could pull off those massive gigs with ease, saying, “I can’t play places like Birmingham NEC. The only group I’ve seen come over reasonably well there was Dire Straits, and I’ve seen quite a few people, including Dylan, David Bowie and Foreigner. That size of gig is a little out of order now, in Britain at least.”
Given the fact that Birmingham NEC is one of the most open venues imaginable, though, it’s not like Plant couldn’t hold his own, either. If you look back at the handful of shows that Zeppelin played at Knebworth during their prime, they still knew what they were doing, even if they were flying blind and trying out material that most fans would have never thought they could pull off like ‘Achilles Last Stand’.
But Dire Straits playing those huge venues had a lot more to do with their approach to music. None of them needed to be an Olympian athlete on their instrument because it was always about what felt right to them, and regardless of how many times they got onstage, they could always reproduce the kind of sounds that came alive in those massive venues.