Nope, just engineering to do not much more for warranty. Turbo engines arent inherently unreliable (tho you might need to replace the turbo itself every 100-200k so still more expensive to maintain), just need to build extra strong block and components if you want it to run for a long time.

And why would company do that if that would put it far over warranty period?

>Turbos no longer mean you have to sacrifice fuel economy for performance (unless you have a lead foot).

That's incorrect. Virtually every turbo'd gas car runs slightly richer than stoich to use the unburnt fuel to manage temp/knock. Diesels, you actually get more efficiency out of with a turbo for free. With gas you're practically guaranteed to be throwing fuel out the pipe.