The situation has historically been the exact opposite for WiFi drivers, where Broadcom is the obstinate closed-source vendor and Qualcomm-Atheros is the most open-source friendly vendor in that market.
Post qualcomm takover, their new chipsets are all heavily locked down, and only functional with a huge closed source driver-esque firmware megablob that is buggy and preforms poorly. You cant even set your mac address anymore.
Tying qualcomm to the atheros reputation for open source friendly chipsets is an insult.
Everybody uses proprietary firmware for their 802.11ac adapters. Mediatek has gotten some interest because the firmware for some of their 802.11ac chips is fairly minimal and doesn't get in the way of substantially improving the open-source drivers.