I have been around alternative fuels and vehicle propulsion systems for 20 years and still cannot support any new technology fully as each has significant drawbacks. Hybrid vehicles work OK in city driving but not on the highway, and the payback in fuel economy savings is about 10 years. Plus, those cars are small compared to the needs of a family, so you need multiple vehicles for commute vs moving the family. Not efficient. Smaller turbocharged engines do give better fuel economy and more power per liter displacement, but turbochargers are fragile beasts susceptible to bearing failures and the like costing a lot more to fix than the fuel saved. Electric Vehicles have a myriad of issues including the fact that they actually emit more CO2 than conventional vehicles when used in states that burn coal or NG for electricity production. So much for saving the planet. Plus, most people don't drive Tesla's for the best economy, they drive them like race cars using much more energy than they should because they accelerate so well. There are so many issues with EV's that I cannot begin to discuss them. With so much more conventional fuels being discovered and produced, we are not running out of energy and fuel prices <$2/gal show that is the case. Corrected for inflation, we are not paying any more for fuel than we were in 1980. And would be paying less if there weren't so many taxes and restriction placed on crude oil production. Vehicle manufacturers have to consider many issues when planning future powertrains, but what is the real driver is what the marketplace wants. And pickup trucks with V8's and diesels are the most popular vehicles right now.
There are some advanced valve timing approaches that may keep the V8 in place for a few more years. These include electronic and pneumatic valve control that will tailor valve timing to exactly the conditions needed. Taking valve timing away from a camshaft allows all types of variations which should give more specific power (HP/CI) from an internal combustion engine. This could be applied to both diesel and gasoline engines, but reliability and cost have to be proven.
