This doesn't answer the question: which industry professionals prototype their embedded products using an Arduino?

The only two examples I can thing of are not Arduino and not prototypes (these are production units) but the Wi-Fi module for Garo EV chargers is a Raspberry Pi with an angled GPIO header.[0]

Also, the Wi-Fi module for Ebeco floor heating thermostats is a custom PCB with a SMD mounted ESP32 board. They never show that side of the PCB in the photos online but I have one and that's what it is.[1]

[0]: https://www.garo.se/sv/proffs/produkter/e-mobility/tillbehor...

[1]: https://www.ebeco.com/products/accessories/eb-connect-wifi

You... don't?

You use Arduino for their super good support and documentation while you're building your device. It's only for prototypes.

You can buy $4 boards off Aliexpress, but then you have to deal with poor documentation, clone boards, buggy code, etc.

I lost 4 days trying to make an SPI screen just "work", until I realized my clone board was outputting the signals offset due to a hardware bug.

Not a product in itself but I've seen one used to prototype an automated testing solution for existing hardware.

I'm not sure why it'd be particularly surprising? Their whole thing is being easy to use and quick to iterate with.

Like, you want their names?