In which case this is your answer; they're worried about knockoffs, because without the firmware logic their devices are simple commodities, ie don't really have strong differentiators from the competition.
The easiest example being b/g channel 13. You're permitted to use it for WiFi in most of the world, but not North America. Keeping the firmware proprietary and "secure" is likely an important part of their FCC/IC certifications.
1. https://apps.fcc.gov/eas/comments/GetPublishedDocument.html?...
Similarly, cheaper chips often don't support optional performance-enhancing features at layers 2 and 3 (link and MAC) that boost performance without any hardware investment.