Are you saying that a regular door handle makes it more likely that a criminal will open your door, so that's a problem with standard car doors as well?

Not that the door design is perfect, but there's no reason they can't:

- put a door handle on the outside, along with a keyhole (or possibly just a fingertip-lip on the window?)

- ...which would allow you to slide the window & door along their tracks manually if needed.

If you've ever had a powered garage door, it's more or less the same thing; sometimes the power will be out, so you have to be able to tug it up anyway (with a bit of extra drag from the motor, but hey, it's on springs so it's not too heavy).