Juggling European footy will quickly bring that points tally back towards us. If United win even half of those dominated home draws, we're close to them. If De Bruyne puts City 2-0 up against Chelsea it's a 6 pointer and a likely different psychological path. Loads of if's & maybe's, loads of little factors that have contributed to what has been a nice favourable season for Chelsea, but take nothing away from them, they've been ruthless.
But I can still sorta see the bookies logic tbh. The table doesn't tell the complete story. No doubt both clubs will go out on a limb to improve too this summer. Arsenal would be a mad bet given their current state. Spurs have a quality coach & squad, but they're still Spurs, the team to finish 3rd in a 2 horse race. Chelsea will have it tougher next season. It's no coincidence that Liverpool's better league campaigns coincide with no European footy, so it would leave the two Manc clubs as likely candidates along with Chelsea.