I took an '86 w124 up to 300k miles and a c126 up to 220k, all while owning my 94 cobra (since 96). I currently daily a new volvo s80. All of the foreign stuff gets parked outside, the cobra is in the garage.
Nothing wrong with putting miles on other cars to preserve your mach or other rare stang IMO. Old Benzes are pretty reliable, especially the w124; I would look for a diesel version of that chassis if you insist on burning oil. Dodge used the same multi link suspension well into the 2000s, so they still feel like driving a modern car. Airbag(s). Parts are cheap too..