There was a great long article in Friday or Saturday's Dallas newspaper about Jerry World stadium. It's "the elephant in the room". Local media, when being honest, have said the same thing and it's obvious for those who know. Jerry World stadium is terrible for football. It's not a winning or football environment. For that fact it has to have an effect on the team culture and wins/losses.
Everyone says the acoustics are terrible for live concerts.
The bottom line is that new stadium design is one big blunder by JJ. Physically it is a huge fancy building (actually an ugly dome) with excessive bells and wistles but no good function to it.
Everyone in football from top to bottom admires the stadium in Seattle with the noise, 12th man, etc. Those fans and players love it. Even when it is raining and cold that stadium is packed with fans having a grand old time. JJ built the absolute polar opposite of that kind of football here.
Will JJ's stadium forever be something keeping the team from being as good as it could be?? Yes! it most definitely will be a contributing factor in my opinion.