The 5VZFE has gone over a million miles in some cases so it is reliable. As long as you attend to the well known catastrophic killers of these things -- frame / axle rot, LBJ, pink milkshake, rotted out rear heater lines that dump all your coolant, it should last a long time, unless you are unlucky like the earlier person who threw a rod. And plasticky parts will break with age that will need to be replaced on an ongoing basis, but that will cost less than buying a new SUV which won't be as good as these.

Most people won't tend to the above catastrophic issues so their trucks will end up in the junkyard soon. Then only enthusiasts will own them which means they will become collector's items.

This will happen first in the east where they rust out and later in California.