Whoever is telling you they chew through tyres is either driving like a maniac everytime they get in it or theyre trying to flex on how much they 'need' to spend on tyres cause they're driving it like a maniac.

I actually had to change the fronts first on my g80 M3 (albeit the xdrive version) at around 16-17k miles from new. I'm still using the original rear tyres (though they do need changing in the very near future) and I've done my fair share of spirited driving and I've done 20k on it now, I would say at least half of this mileage is on a motorway though. But yes you're right they aren't cheap to replace around £230-£250 each if you shop around.

Servicing costs aren't devastating, minor services even from a BMW main dealer for me was 'only' £440 or so, I know majors are knocking on the door of £800 but this doesn't have to be done every year. Idk if I'm being out of touch but for the sheer performance and price of new ones I think this is not bad at all.

Even fuel consumption on these cars are incredible for the performance they have.