There is to an extent, it's just a matter of harnessing it and increasing it. Past games at Wembley attracted about 30,000 fans from southern locales and no doubt many from Midland ones too, plus there were 33,758 at the 2000 RLWC opener at Twickenham for a night game despite the near impossibility of northern fans getting down for it at the time. That crowd was only 7500 less than the 1995 opener at Wembley, so quite good in the circumstances. That's something they can build on.
There's no problem structuring the tournament so that barring a huge upset the big 3 will make the semi-finals. The key is to make the games into events that people will want to see regardless (it is a World Cup after all!) and sell them out in advance. They have 3 years to plan this and they appear to have government backing lined up too. If they can't work out how to make one game work at a Midland venue, what does that say about the sport and its' long-term prospects in the UK?