High RPMs at highway speed?

["Clough, Samuel" <SClough@irps.atl.invesco.com>]

Ok, so I've always wondered this, but I've never asked anybody and I figured
it was time to submit my question to the infinite wisdom of the list.  Why
do our cars run such high RPMs on the Interstate?  In the A6 at 80mph it's
turning 3,600.  Should you cruise around 90 (of course totally theoretical)
the RPMs are just about on 4,000.  None of the American or Japanese cars
I've ever driven turn anything like this.  Most of them seem to just be
getting to 3K at around 80/85. It seems to me that a German car designed for
the Autobahn would have a higher top gear.  If I drove this car like I
assume it was intended to be (ie Autobahn) and assuming the gearing between
USA and European cars is similar, I'd be cruising at or over 5k.  I mean how
long can the motors last being driven that way?  It just seems to me that
with the gearing on the car I'm putting unnecessary wear on the motor with
long highway drives.  Am I crazy, or are these cars so bulletproof that they
are immune to the wear affects of higher RPMs?
TIA,
Samuel
95 A6Q (loves the far side of the speedo)

Samuel W. Clough
INVESCO Retirement Plan Services