The basic fact is we need to be a Premier League team now. The gap is huge - maybe not quality wise, but financially. If we don't go up this season, we could get progressively worse while chasing the same goal. The worst case scenario is ending up like Ipswich, whereby you've chased getting promoted again and end up millions in debt while dropping down the table.
Another fact is that the coming summer could (should) see our highest squad turnover in several years, with players leaving on frees, their loans ending, etc. That becomes an easier prospect if you're in the Premier League; players are more likely to sign, and you can afford much better wages and bonuses. If we're still in the Championship, not only will we struggle to attract players while having to reduce the wage bill, but we'll lose more players because people like Dawson, Rodriguez, Hegazi, etc still think they're Premier League players.