-You think you know how it works. But lots of little hardware quirks will still bite you in the ass.
-This means that all your data has to fit in your code space, so you either trim code or you trim data.
-Generally you wouldn't do dynamic data at all, ever, so instead you were stuck constantly balancing and tweaking constant arrays of data and balancing them against everything else in the world. Do I allow 3 entries for explosion effects? Or 5? Am I willing to have one less enemy on screen for those extra effects?
-There's also often very few registers and an extremely limited stack.
I mean, I'm not saying you are wrong, and from certain angles sure it's easier to write in 8 bit assembler vs modern day high level languages. But there's also things to consider that happen above the language. What happens when there's a bug in some code and you have to hand it to a programmer who isn't familiar with that code? What happens when two subroutines are too far away from each other to jump? What happens when you get graphic corruption bugs and don't have the modern conveniences of data breakpoints and other tools?