i still don't understand this statement - but there is your quote.
displacement isn't the be all and end all of power production. it is however the be all and end all of TORQUE production. so what are we talking about here?
a turbo on a 3.0L effectively makes it a double-the-original-capacity engine at 1 bar of boost. running 2 bar boost would put it up there with a 7.5L engine power production wise - both engines being of similar spec of course *
a 7.0L engine with "only" 0.5bar boost would still be equal to a 10.0L engine power production wise *
so explain the more fuel thing again please?
*please note this is a rule of thumb guide only and many conditions will vary causing power gain or loss like compressor selection, intake air temps and tuning