I do not agree with your statement, carbs work on vacuum to meter their fuel, they intentionally design restriction into them in order to do their best at metering fuel. An EFI is a lot less restricted than a carb setup for this reason - on top of that metering/controlling the AF and timing can be a lot more precise/optimal which will produce more HP.
I will agree that it is a lot less expensive to produce more HP with a carb than an EFI setup because of limitations of the factory equipment and costs of equipment/components to upgrade.
Walz
I think your logic of how a carb works is on track but maybe a little off. They don't technically work on "vacuum", they work on atmospheric pressure (which of course, creates vacuum). I'm not picking a fight but what exactly do you think is a restriction in a carb? Also remember that carb sizing is key in making the best performance. Yeah, a 500cfm carb on an 8k race engine would be a restriction...but an 850 wouldn't necessarily be.
Typically, EFI makes more torque and has a broader torque curve...or in other words makes more torque at lower RPM and carries it longer than a carb setup...this is mostly due to the longer runners in your typical EFI intake. Build an EFI setup with a carbed intake that's drilled and tapped for injectors and run a throttle body on top of it, and there wouldn't be ANY difference here depending on the combo. Of course, the more radical you get with cams and air flow and RPM, the harder it gets to make a carbed setup streetable....again, i'm not saying carbs are better, just not as inferior as some people make them out to be. You surely could build 1000hp EFI engine and tune it to purr like a kitten, whereas you're not likely to build that kind of power with a carb and have it very streetable.
There's a line somewhere, where the performance gets to a level where no amount of tuning can make a carb run as well as EFI for all around driving. For max power and racing, there's not so much of a line. For your typical enthusiast, building a typical 300-400hp engine, it's down right silly to say you can't build a carbed setup to run as well and be as drivable as an EFI setup. You WILL get better mileage with the EFI setup...i'll give you that, but again a LOT of that is in the tune and making sure the a/f ratio is spot on. If it is then the carb is doing the same thing EFI is doing, except mechanically instead of with an ECU.
I really wish i could afford a Webber setup so i could really stir the pot