That’s probably true but it cuts both ways too.
I don’t know if the lack of copy left license is the problem as much as the momentum.
The various Unix and BSD wars (that were predicated on a much different licensing challenge) and splintering of the communities has meant there was never a big way for developer or even manufacturer interest to really focus.
OpenBSD has a very different philosophy related to drivers than FreeBSD and for very understandable reasons, most of the BSDs don’t want to use or touch GPL code.
The copyleft nature of the GPL definitely helped Linux, but I don’t think it’s the only reason Linux was successful.
But Linux got its shit together first and was able to benefit from that. Apple and to a lesser-extent, Solaris, show that you can still have broader hardware support and drivers without a copyleft license.
I do think that if companies could easily port their Linux drivers, you’d see that happen. That’s absolutely a consequence of the license choice (and it’s a consequence from either license decision). But if there is a market for the BSDs in a particular area, I do think you see companies making drivers.
The reality is, the market for people running FreeBSD on laptops is pretty small and probably not worth it for a lot of WiFi chipset makers. But if you had a specific industry where FreeBSD was widely deployed, I do think you’d have broader hardware support for things important to that industry, if nothing else.