I'm not convinced it's an assembly language advantage per se. Most of these very low power MCUs now come in variants with ridiculous amounts of flash that negat

I'm not convinced it's an assembly language advantage per se. Most of these very low power MCUs now come in variants with ridiculous amounts of flash that negate the space advantage of hand tuned assembly. The binary a C compiler will generate will be bloated but the tight loops that matter will run with comparable speed and induction count, and the extra dead code and flash will not impact power draw. So you are down to C knowledge, a datasheet and a register and pin map, which many people in their 20s definitely knew how to handle 10 years ago, when I used to work for Freescale/NXP. To expedite that further you can go with Processor Expert, which will generate C code and abstract much of the datasheet swordsmanship. Can be finicky to setup, but the "drivers" you get (C routines) benefit from long debugging sessions and lessons we learned about the "proper" way to use a peripheral, sometimes using info from the hardware teams that was not in any datasheet. The thing to win with newer, power hungry platforms is the so called "race to idle". They are so powerful and have such efficient low power modes that the best battery life is obtained by cramming as much work in a wakeup as possible and then going to sleep, as opposed to having an exceptionally low power machine that is awake most of the time. So someone with an 80s paradigm might need to adjust to this reality. Thousands of units is nothing and definitely not enough to (profitably) stay on hand tuned assembly.