The most relevant part for me is this cherry picked line from the article:

    ...
    Consequently, the megaAVR remains the most open-source
    8-bit microcontroller on the market — by a long shot.
    ...

Even though the Atmel AVRs aren't the fastest, or cheapest (in cost per unit) or the toolchain isn't the easiest to use or the debugging capabilities aren't as good, the fact that it's open-source makes it win, hands down. There's a reason why nearly every hobby electronics project you see has an Arduino in it. Assuming the Arduino IDE is installed and permissions issues have been resolved, you can go from unboxing your Arduino to making it blink in under 60 seconds.

In addition, places like Adafruit [1] and Sparkfun [2] build their own boards and make most of their code free/libre/open-source [3] [4], with a large focus on Arduino.

It'll be interesting to see how the electronics market evolves when the current and subsequent generations are trained on AVRs.

[1] https://www.adafruit.com/

[2] https://www.sparkfun.com/

[3] https://github.com/adafruit

[4] https://github.com/sparkfun