But can't the vehicle carry them to Mars? Kind of like the airbag system for one of the rovers, can't remember which one (Curiosity?)

Or even better, how about getting it to land sideways on purpose? I don't see how that would be more difficult than doing it upright.

Imagine the material that a coke can is made off.

Now imagine a cylinder made of that material 3-4 times wider than a barrel and 20-30ft high.

That's why you can't land them sideways they'd just crush themselves.

I guess you are right. It wouldn't make sense to make a rocket that can withstand vertical AND horizontal forces. That would be like launching a brick I guess.

Thanks for the pointer.