One thing for sure... the league could migrate to smaller stadia in the larger towns, because they won't need big stadia. That's not the worst thing, really, because the likely fans are more likely to appreciate a grass-roots approach. After all, the teams have mostly retrenched to Germany because of lack of fans elsewhere.
Actually, there is another thing going for Germany. Pointyball in England and Scotland wasn't going to steal fans from rugby... and there's already the battle between Rugby Union and Rugby League on the isles. Germans are often bigger and more athletic... so why hasn't rugby taken hold there? Germany has apparently never come close to qualifying for the rugby World Cup. I find that fascinating. After all, France loves their rugby, Italy has taken to it fairly well, and there's usually an Eastern European representative. I don't get it.
It won't happen. NFL Europa is slowly becoming NFL Germany. Besides the Sacramento Surge became the Gold Miners and had to move due to poor attendance. Best bet now is that one of the NFL teams move to Sacramento or the AAFL (if it ever gets off the ground) puts a team at Hornets' Field.