Wow, way to understate the shit out of that numbers! Good job, good effort!
Promotion gets you a shit ton more money and a shit ton more prestige, which will attract a better caliber of player than you could have gotten in the lower league. The jump from the Championship to the Premiership is fucking massive in terms of how valuable it is to a club.
Leicester is actually owned by a very rich man that has promised to invest hundreds of millions into the club/squad in order to get them into Europe in the next 5 years, which would be amazing from a club from their area of England.