Hey fellas
Yeah I can see the point, but really, its not hard to have a forced induction engine perform well in cruise conditions.
The port shaping, the camshaft timing and so on is designed differently to a NA motor and you'll find that fairly mild duration and mild port work is best for forced induction.
What gives the power is slamming air into the combustion chamber at high pressures, not fiddling round with high duration cams to try and suck more in at near atmo conditions. And lets face it, even a fully modded atmo engine is not going to have a volumetric efficiency much above 1.00
When it comes to longevity I think water injection is an excellent safety buffer for forced induction cars. Despite being a good knock suppressant its effects on exhaust gas temperature and valve temps to name a few things is significant.
The rotary engine does not have the same brake specific fuel consumption as a piston engine so it always use more fuel than an equivilant piston motor. BUT what can be assured is that in offboost conditions a performance turbo vehicle will be fuel efficient provided the porting, valve timing etcetc is all optimised for a forced induction type engine (no drag spec). It is gaurenteed to be far more fuel efficient than the same engine NA with bigger duration cams and so on.
If you sit down and do a proper analysis of the additional loads placed by forced induction you will find that the power load is mostly offest by the inertial load anyway. You are putting more power into the cooling system, the pistons are stressed more, and you have
oil issues and the like but in general if those things are engineered properly a turbo motor will last almost as long as an NA motor provided it doesnt detonate the fuel.