Everything is difficult until it becomes easy. Carbs are simple because they are deemed to be simple. They are however, forgiving. The knowledge to tune a carb is not genetically implanted; there is always a learning curve. How many people truly know how to take advantage of every feature on 3-circuit carb?
I think that if one compares the cost of mechanical injection setup to that of a pair of Dominators, the price will be similar when pumps, regulators, etc. are factored into the equation.
Tuning MI is a different way of thinking from tuning a carb. No more difficult, just different. People are reluctant to change. I think THAT is the greatest challenge. MI is not for the MPG freaks. The throttle response is way crisper than with anything else I have heard running.
EFI is where it is all going. But you not only need to be a tuner, but a fluid-dynamicist, thermal-dynamicist, and a computer programmer to be able to tune your engine. EFI is not for the faint of heart nor shallow pockets, but you can dial in the exact Air/Fuel Ratio for any engine condition.
As for me, I love my Enderle Birdcatcher MI on a blower motor. I hope to one day build a NA IR stack injector engine like Beaveretriever's. MI sets you apart from the masses. Some day, I hope to play with the EFI stuff, but that probably won’t happen until I win the PowerBall. Unfortunately, there will still be carbs in my future. Its all good though.