To a certain degree you're absolutely right. All mechanical stuff will have issues and eventually fail.
The point that I'm making though, is that diesel emissions equipment have nearly ruined the purpose of owning a diesel. Extended engine life, better fuel mileage, ect.
Like any new product, system, design, ect, there will be a trial and error period that needs to pass before they have worked the bugs out of most designs.
There are thousands and thousands of early emissions compliant diesel motors out there, in every industry and sector that are ticking time bombs. If they get fixed under warranty, great, but if they fail out of warranty and prematurely, the consumer takes it in the shorts.
The emissions designs are getting better, but until there is more long term solid proof and a design that will work, I'm staying away from new for awhile longer.