A couple of things make me think that this could be incorrect. Firstly we will have a massive shake-up of players next season. 10 are out of contract we may keep one or two (depending on what we offer Jags and Eastwood) but there will be clear out of players. In CWAK style the least used players go out making more wage funds available for two or three first team challengers to come in. This is why we have had the continual rise, Ebanks Landel out Stearman in, Stearman out Egan in etc.
Secondly because we have replaced the revolving door to the managers office that all other prem clubs seem to have well greased we have a structure, a plan, continual improvement and a very fit and highly motivated squad that will get fitter, more motivated, increase in skill level and able to adapt to tactics. So the usual pessimism that accompanies being a Blade has mostly gone to a small niggle (the little what if!). But think of our squad under Bassett we were not able to survive after losing Brian Deane, but you can take any two out of the outfield players in the first eleven and there are two replacements dying to make an impression.
What an enviable position that would be to any manager coming into a club. So we have a culture and structure in place that has proven to be successful and keeps improving. Therefore seasons like this could just continue. Who knows?