[blhack]

>I disagree. Everything you listed a) can't be used for products, b) doesn't let you make progress beyond "oh look, I lit up an LED!".

Nonsense. This device: http://nanthealth.com/vitality/, which was a "big deal" to telemedicine folks (and is still a good product, please somebody reproduce it for cheap), and resulted in a MASSIVE exit for the people who founded it, was built around an atmega328p.

I would be good money that it was prototyped on an arduino.

This: https://www.industrialshields.com/ is based on an arduino. Like an actual, blue, retail arduino.

I've personally built one-offs for advertising installations (products for sure, but probably not exactly what you meant), that are full of arduinos.

>doesn't let you make progress beyond "oh look, I lit up an LED!".

This is wrong enough to make me think that you either don't actually know what a microcontroller is, or are being deliberately misleading.