No Replacement for Displacement (myth or fact)

Displacement is irrelevant once you know what you want to do. Then it's optimizing the package for what you have to get what you want. The analogy works if you're the "bolt in and go" guy. An even in that case, it's not universal. My 340s used to spank big blocks all the time on teh street. Because I knew how to drive them to get the power I needed.
Once you get talking about a needed result - say - to accelerate a given weight to 150mph in 1320'... then it's easy. It's just math. And you can use 200" and wind it to 15Krpms, or you can use 534" and keep it under 6K. I know of some record setting Ford 302s an 351 Clevelands that only were "fast" because of the rpm ranges they were built to operate in, and put in a package that enabled that power to get to the tires, and the tires to stick. Same thing with cylinder head designs and everything else.
The right package is always the fastest. Doesn't matter how big it is.
but yes, size matters in the girl bit...lol.