I disagree. There is very little loyalty in football- if they find out their squad is way too thin for Premier League football, and they either don't land the targets they want in the Summer, or the Board decides not to massively invest then they could very well find themselves adrift at the bottom at Christmas. In which case there is every chance it will be "Thanks for the promotions but we're going to go with someone who can find a way of keeping us up".You'd be off your rocker to leave the club you won promotion with for any job especially Chelsea unless your sole motivation was money,I don't know anything at all about this bloke but if he leaves Ipswich for us I wouldn't get too attached to him.
I'd be well miffed if I were a tractor boy and as a football fan I'd like to see him have at least one season in the EPL managing the club he's dragged out of the gutter to where they'll be next season. My dislike of Chelsea continues to grow and I can't believe I'm saying this but they've managed to overtake Palace in my small book of clubs I care not for.
I think it's a very sensible time to leave that job, as it is highly likely it's only going to go downhill from here. He will burn some serious bridges in doing it though.