That isn't entirely true. It only boils down to that problem when they hit East Germany - there they always struggle to sell out venues. Even in 1995, at their peak here in Germany, they "only" played the Waldbühne in Berlin twice (capacity around 20,000), while selling out the Weserstadion in Bremen twice and fitting around 4 times as many people in there over the cause of the 2 nights.
This tour they have even scheduled a lot of shows in Eastern Europe and with concerts in their home country like Bulgaria or Poland many fans just won't bother traveling to Berlin to see the band. Even booking that stadium seemed ridiculous to me from the beginning since Jon should be aware of how they always struggled to sell tickets in that region. Well, a guy who thinks he can sell out the desert doesn't seem to notice though