This concern has been answered eloquently by a contributor to
these newsgroups a few years ago.  Sorry I can't name the author, but
that person hit the nail squarely on the head with these words:

    ".........more importantly than that, you've got to have the
insight and wisdom to know when something has been developed to the
point where further development amounts to pointless engineering
masturbation.

    "The hydraulic brake system is a textbook model of development
to perfection. So was the hydromechanical automatic transmission --
computerisation of the automatic transmission has taken away
three-for-one in durability, dependability and cost of repair what
little it has given us. We know how to make steering systems that work
and essentially never give trouble. There is, therefore, no valid
reason for steer-by-wire."

Hi there.

I have been looking at the new Honda Civic, it's pretty sweet, and the
welds and everything are as nice as anything I have ever seen. I just
have a question about the "Drive by wire" system that they are supposed
to have.

What happens if the Engine dies on you? In my current car, my timing
chip went once and the engine went out. I had enough steering control
left, even without power steering, to pull my car over before it came
to a stop. If the drive by wire system has no "real" or active
connection, how can it work if the engine or electronics quit on you?
Are there any backups built into the system in case any of that stuff
happens? And what if your battery dies and you need to push the car?
Can you turn the steering wheel to adjust your wheels when you push the
car?

Much thanks, sorry to bother.

David