How could it possibly be detrimental for Broadcom to have free software drivers?
This article is a poignant example that it is detrimental for them to continue to keep their drivers proprietary.
It isn't that it would be realistically detrimental, it just has no value to the individual attempting to change the established course of the ship
Manufacturers currently have no choice but to ship devices running vulnerable application software that communicates with remote devices using vulnerable protocols. This is facilitated by vulnerable operating systems running many vulnerable device drivers communicate with devices that themselves have embedded processors running yet more vulnerable software.
All manufacturers can do is keep patching the morass of code that their offering depends on, but most device manufactures can't even manage that, or if they can they are unable do it fast enough and unwilling to do it for long enough.
How many of your non-professionally-technical friends could tell you the manufacturer of their WiFi chip? Is it on the box? Could they even tell you who Broadcom is?
"Intel NIC" only recently became a very minor selling point in enthusiast desktop motherboards. I'm not holding out hope this is going to follow a more informed curve.
The gatekeepers (manufacturers) are the only ones informed enough to make the decision en mass. And they're not going to do so without a market reason. So barring something like "Broadcom stops providing security updates" or "New law holds device manufacturers liable for security bugs" they're going to save the few cents on BoM and continue using them.