I did statistical process quality control for a living for 10 years, and now do cost savings analysis.
I wish we had good data for a decision point for the pump failure rates and MTF (mean time to failure). As a general observation, while most people do a good job in changing engine oil/filters, coolant is a neglected item. It does not help that the coolants today are advertised as "lifetime" or 100k mile changes; that is so far out that most folks just plain forget. Other people are good at following prescribed changes, but again, with the coolant life cycle being so long, it's not really known how the pump failure would relate to the coolant change regime.
For those who do change their coolant preemptively, much sooner than Ford recommends, we'd have to see what kind of correlation would exist between coolant life and pump life. So we have a few groups to consider, and I suspect the data is lacking to make a good determination as to "when" a pump will fail.
Correlation does not equate to causation, but without correlation there can be no causation. If we could find correlation between coolant life and pump life, we'd at least have some track to follow. Sadly, I doubt the data is available to us.
All water pumps fail. The issue with these is that they don't always give the tale-tell weep leak to let us know. If we're lucky, they leak via the weep hole and we get a hint of impending doom. The problem is that they don't always do this; some will leak on the opposite seal and leak into the engine. While oil analysis may pick up on this, it would have to be a slow enough enough that discovery predates doom. That may or may not be true.
The nature of the pump being buried inside the engine is a nod to packaging. Can't have it all, folks. Things take up space, and putting the pump inside saves space for any particular chassis package.
The Achilles heel in an otherwise excellent engine.
I bought my two Taurus cars knowing this going in. I hope to catch the issues prior to catastrophe, and change out preventative. Only time will tell ...
I knew it going in, as well, having an 08 Edge of my estranged wife's. I try to be proactive and monitor for potential problems, since I went ahead and picked up the 08 Taurus. Strangely, our cars were built the same day in two different plants.
But I do love the way the car drives, especially after I had an alignment that corrected serious misalignment problems. When I got it, it wouldn't break 23 mpg in highway driving. After new plugs, alignment, and an air filter change, my last trip netted a nice 29.2, on the same routes for testing. It's a fine road car.