> You can make a low volume product by buying a bunch of Arduinos as your controller. You just stick them in the device. There's no license issue.
Note that the Arduino libraries are LGPL licensed. Unless you have a commercial agreement with Arduino, you have to distribute your firmware to your customers as object files so it can be linked to updated/modified versions of the Arduino libraries. This means that I wouldn't use Arduino for a shipping product unless you're fine with the firmware on the device being publicly available.
That's not my reading of https://support.arduino.cc/hc/en-us/articles/4415094490770-L.... The LGPL is usually a requirement to publish your modifications to the LGPL licensed code, but not necessarily your binary blobs. And for some low-volume Arduino based products, the software isn't the valuable part of the project, anyway.