Come on mate, is not as if Van Halen is wildly popular here either, I doubt one is more popular than the other to really count it

Re Van Halen/Def Leppard. Van Halen is my second favourite band but it is commonly known that they did not do the ground work outside the US. There is not a strong Van Halen fan base in much of Europe, Asia, or South America, of course some countries took to the band more but Van Halen is an American band in that they were only ever interested in America.

Yes their fees are high, and it is a part of the reason they do not tour outside the US, but they are rarely picked up for festivals either outside the US. Firstly the band is and mostly always has been happy to just tour the US, and secondly there is not enough interest to sustain a long tour overseas.

The only way a European tour would work for Van Halen if it was maybe one or two shows with limited capacity per country. I am not sure even that would shift loads of tickets.

Def Leppard is well liked in Europe, so I imagine they could out tour Van Halen there, although we will never know.