The vendor's choice of hardware licensing, software licensing, and effort to work with the mainline kernel plays big roles in this compatibility. You almost never hear about Linux having a problem with Intel graphics, but you do with Nvidia. You also almost never hear about issues with Intel 802.11 cards, but you do with Realtek.

It's not Linux's fault, really. If you have a bad neighbor distributing proprietary stuff that completely refuses to add support or work with you, the next worst step is having users that scapegoat Linux and blame it for not supporting said hardware.

Thankfully, there has been a big push for Linux compatibility lately, so things have gotten better, even with closed hardware and proprietary vendor blob drivers. But it is often a nightmare of licensing issues, often produces unstable or poor-performing drivers, and the effort to make it work better often lands on Linux, not the vendor.

Look at this post. Not once was the license of the Brother or HP drivers discussed. Do you know what they are? Are the sources available? Are you running blobs? Was the support reverse engineered by users, or offered by the vendors? Before your moment of appreciation, you should take two steps back and look at the big picture.

While Linux runs on approximately 2% of workstations as of this writing, it is the dominant platform that runs the Internet, and is often the operating system of choice for embedded platforms. A long time ago, Linux support was mostly fostered by volunteers, but we often see hardware support as something a responsible vendor would maintain now.

But that said, I really do appreciate the ease of Linux support. DKMS has helped this significantly, too. Most of the flow is to install a package and possibly reboot. The kind people of your operating system, the strong and persistent efforts of kernel maintainers, and possibility the work done by vendors has made Linux compatibility an act of grace when everything falls in place.