The OEM, Vredestein make collapsable spares in some very large sizes for latest cars.
They may have one in the correct size and offset that fits the car, but it may not ( probably) fit inside the spare wheel well,
Hence no M-B option.
I think this was true of the SLK32 too, so it has long been a trade-off decision on the AMG model.
Fit a towbar, make up a mounting bracket to hold a spare wheel for those long trans-siberian, cross-continental trips.
Is it really true that nowhere in UK or EU is more than 5 minutes from a tyre shop?
All the car manufacturers seem to think so.
That doesn’t apply in Australia.
Manufacturers are also probably considering that fewer and fewer people have the skill or inclination to change their own flat wheels.
Almost everyone has some sort of roadside assistance policy.
And it’s dangerous too, as I recall we have had a couple of people killed recently trying to change a wheel on the side of a freway and getting clipped.
Always drive on gently to somewhere it is safe to stop.
It won’t hurt the tyre, it is already stuffed.
My last flat happened in a 3km tunnel. No way I was stopping there, Hazard flashers on, get into slow lane, slow to 40 kph, take first exit
at end of tunnel, changed tyre in a backstreet, safe, easy, no risk or stress.