I know about the Mercedes but did not know about the Suzuki. My main point though is that this is not a feature in your bog standard Honda Civic or Toyota Corolla or Ford Fusion. I think it should be, it's a huge safety and convenience feature. That it is not in your average car implies it's probably too expensive for the utility it offers the average person.

Personally I solved the problem by buying a lithium ion car starter for both of our cars. Works great, but I really would prefer the cars just had some redundancy built in.