@sally @adachi >No, they did remove all proprietary drivers and software
The Linux developers did no such thing.

A couple years ago they moved some of the proprietary peripheral software to "linux-firmware", but not all of it and they keep occasionally array-encoding proprietary software and adding it - such added software is only occasionally moved to "linux-firmware" - typically it stays there unless and until it becomes totally obsolete (i.e. appletalk).

Many drivers in Linux are only half of the driver - the other half is proprietary peripheral software that runs on the peripheral device and those drivers are therefore proprietary.