Going back a bit in the conversation - but the crazy Premier League broadcast deals mean that the playing field is not as even in the Championship as it was back then.
Luton had total revenues last season of about £18m (so did Coventry). And spent about that on wages.
Norwich and Watford, by contrast, got Premier League parachute payments of more than £40m alone! Their overall revenues were likely 3-4x this season what Luton made.
Most of the 'smaller' clubs that have made it to the Premiership have either been bankrolled by rich owners (e.g. Bournemouth) or had built up their club infrastructure over years and years - including building new grounds and outstanding recruitment structures - so that they were able to compete at Championship level (e.g. Brentford, Brighton).
I think the last Championship club to outperform their budget as much as Luton did this year was probably Blackpool about a dozen years ago.....and even then, back then parachute payments weren't nearly as high. It's possible that noone's ever won promotion to the top division with as big a financial deficit as Luton had this season.
Jealous? For sure. But also really glad to see that it's still possible to go from bottom-to-top with just good management, and without a complete restructuring of the club. I hope they cause some havoc next year and make a decent fist of staying up. But even if they don't, one year in the PL will pay for their new ground!