Why hasn't anyone released a HD truck with a Turbo V8?

There is a 5.0 ecoboost in the works.

http://horsepowerkings.com/the-f-150-raptor-will-receive-the-ecoboost-5-0-twin-turbo-v8-in-2018/

Or you could just go to Nelson Racing Engines and have him install one of these in your truck, then you can pass all the diesels on the hills.

http://www.nelsonracingengines.com/pricesheets/lsx/dailydriver/tt/dds_364lsx_tt.pdf