It seems a reasonable theory that if we were to go up this season, as unlikely as that appears as things stand, we'd get battered in the Premier League unless we revamped not just the team but half the first team squad, and therefore we might be better staying down for another season to regroup under new owners and a new management team. I can see some logic in that.
Leaving aside the sour grapesy 'okay we failed to get promoted but we didn't want promotion anyway' aspect to it, as each season goes by in the Championship we fall further behind those we're trying to catch. Another season of attempted strengthening for us is another season of the same for everyone else. We may get stronger ourselves but there's no guarantee that that puts us ahead of the rest. You have to consider that if we do stay down, some of our better players will leave which will, at least initially, make us weaker than we were to start with.
On balance I'd much much rather have promotion this season. I don't see that another season in the Championship will necessarily make us better prepared for survival in the Premier League should we reach it. And in any case why assume that we'd get promoted next season? As we've seen, one season down here can become two and then three.