Nordic’s pretty good. It’s not $5/module - closer to $15 - but is very good from a low-level embedded perspective. Their toolchain is first-rate and may have been validated by your target audience.
The first three clauses are fine, essentially BSD-3-clause. Clauses 4 and 5 make it extremely unfriendly to free(-as-in-freedom) projects though. I don't even understand how clause 5 benefits them.
Espressif's devices are definitely not open in any sense of the word, but at least their SDK is under a bog-standard Apache license. Same goes for most of the STM SDK.
Their middleware and DRIVER library is first rate, also BSD: https://github.com/NordicSemiconductor/nrfx/blob/master/LICE...
They are a first-tier active founding member and supporter of the Zephyr RTOS project by the Linux Foundation.
They’ve partnered with Segger for free use of Segger’s embedded studio for Nordic chips.
If a fraction of other companies did a fraction of THAT, Open Source would be soooo far ahead!
Incidentally, do you know why they choose to keep such a restrictive SDK license when they seem otherwise FOSS-friendly?
If I had to hazard a guess, I’d say “evolutionary history”, because that’s almost always the case, in my experience.