My guess is the lawsuit fell flat.
Some lawyer was hoping for big gains, but didn't have a case.
When one buys a new car, part of the contract is the warranty. One can buy an extended warranty if one wishes.
The engine failures weren't critical safety issues.
There are "Lemon Laws". I don't know how often they are invoked. But, they are designed to protect buyers from vehicles that spend more time in the shop than on the road.
Anyway, so once the vehicles are out of warranty, that should end Ford's responsiblity.
Looking at other websites,
6.0 diesel problems--school me please! - Ford Truck Enthusiasts Forums
It looks like many of the issues with the 6.0L engine comes down to maintenance. If they have problems with low fuel pressure, you can bet I would install an auxilliary fuel pressure gauge, and keep my eye on it.
Perhaps not as bomb-proof of an engine as some engines. But, like many things, it will work best if properly maintained.