Traditionally we aren't like other clubs where relegation wouldn't affect us as much because we're used to it. It would have a big impact on what we stand for as a club and on the support from the fans.
It's got to the stage now where relegation would absolutely kill us because of the new Stadium as well as the TV income. We need the Stadium to push us on and relegation would put us on a catastrophic downward spiral that we would never be able to recover from. When Spurs and Chelsea get their new 60,000 Stadiums we will fall even further behind the 'Big 6'. If we don't get our Stadium move as a Premier League Club then we will never have the chance to challenge those clubs ever again in my opinion.