Give it time, we will start to see loads more FI petrol engines, as you say Audi are using a supercharger and a turbo on their 3.0 V6 petrols to give more power than the 4.2 V8 it is replacing and the consumption is up by around 30% too.
BMW have said they are going back to a straight six with FI on it for the next M cars.
The new C180k is a 1.6 with a supercharger, it gets fairly good results and really good consumption.
I think we will see a 350 with supercharger soon, maybe not from AMG, but I reckon we will see one in one of the cars, maybe the new E Coupe or CLS.
Having said that do we really need FI?? if done right isn't a NA engine even sweeter??
Take the new BMW 330i, it is a NA straight six 3 litre petrol. It has 272bhp and does 0-60mph in 6.1 seconds, so almost identical as the twin turbo diesel 335d, while returning absolutely stunning mpg.
The one I had for two days return 38mpg and did 500 miles on one tank.
But again, I bet we see problems with the direct injection system as they get older, but the tech will evolve and mature no doubt.