BTW have owned Ford Mercurys and Lincolns for many years now.
That's a valid point. On both my Taurus and my Camry, the powertrains have been flawless. The Camry has suffered suspension issues and a failed halfaxle that wouldn't have been covered by a powertrain warranty, but would have been covered by a basic warranty if it had lasted long enough.
Still, all else being equal, longer powertrain warranties are a good statement of confidence in your products...
I had a Saab 9000 CS Turbo's transmission fail at about 140,000 miles. Replaced it with a 2000 Navigator so I could tow my boat.