There's one significant problem with these hybrid powertrains, and that is weight. Porsche admitted the electric addition to the 918 V8 engine weighs about 300k

There's one significant problem with these hybrid powertrains, and that is weight. Porsche admitted the electric addition to the 918 V8 engine weighs about 300kg, all considered. The 918 is a very heavy car for what it is, at 1700kg, compared to 1380kg for the Carrera GT (it's ancestor, in a way). The Tesla Model S is also a very heavy car, at 2100kg. However that weight is somewhat offset by its placement, right near the road using a flat floorplan housing all drivetrain components. While the weight can be cancelled out in a straight line because these hybrid drivetrains can provide monumental straight line performance, the weight is still there for turning and braking. Turbos go around the weight issue - in fact, they can make for much lighter powertrains with a smaller displacement for a superior performance. The main problem with turbos, in Ferrari's perspective, mostly relates to the altered emotional connection with the car. No more 9k RPM revving motors with a godly sound, but something tamer (like the McLaren MP4-12C). If you ever got to drive a current generation Ferrari motor, you'd understand instantly why they are so adamant on preserving its character.