brcm80211 contains two separate drivers, brcmsmac and brcmfmac, covering different wireless hardware/ chipset design - you generally don't talk about brcm80211, but the specific driver explicitly. Neither of these are staging drivers, nor developed by Greg, but rather full mainline drivers (for the most part) developed by Broadcom/ Cypress (Infineon).
brcmsmac is a softmac driver, covering a small range of devices - predominantly the BCM4331. Here the firmware is relatively small, more of the functionality is provided by the driver and executed on the host CPU. Broadcom only covered very few chipsets with this driver and pretty much immediately forgot about it after the initial merge - it does not support AP mode.
brcmfmac is a fullmac driver, most of the functionality is contained in the binary firmware uploaded by the driver. Broadcom does indeed do some continued maintenance on this driver, it generally works, but the firmware won't offer all features you might be looking for - but is can (and is) used for AP mode in routers compatible with this driver (most notably the Netgear r8000 with its BCM4366 wireless).
Quite a few Broadcom (softmac-) chipsets are not supported by either of these drivers, including their most popular AP chipset, the BCM4360 (or the older 802.11n chipsets, like the BCM4322). Some of them have some very, very basic support by b43 - but effectively they're not supported (who would be content with 54 MBit/s max on a 802.11ac router, aside from general stability issues with this very basic support).
So yes, the drivers exist - and they are being used on the devices sporting compatible brcmfmac chipsets (r8000, RPi- and sunxi SBCs, etc.), but the bulk of Broadcom routers/ APs remains effectively unsupported, with no hope for improvement.
For details you will find further information via the forum search.