As Miguel de Icaza said in 2012:
> Backwards compatibility is not a sexy problem. It is not even remotely an interesting problem to solve. Nobody wants to do that work, everyone wants to innovate, and be responsible for the next big feature in Linux.
> So Linux was left with idealists that wanted to design the best possible system without having to worry about boring details like support and backwards compatibility.
> Meanwhile, you can still run the 2001 Photoshop that came when XP was launched on Windows 8. And you can still run your old OSX apps on Mountain Lion…”
Yeah Debian is still keeping mostly pro-user but they are not the leader in the cutting edge of development. Distributions innovating more do exist, but they are very small part of the Linux world. Most of it is Redhat, Ubuntu and hardware vendors.
Systemd, GNOME, GPU drivers are very windowsey; tightly coupled big software that one is discouraged to study and improve, almost as bad as their closed source counterparts on Windows.
The problem with old HW support is that the hardware is fine, the drivers are available and fine, but the kernel people decided to throw them out and replace by newer drivers which can run only newer HW products. Developers/vendors could be more user-friendly and keep support for the older hardware since the older compatible drivers exist, but they often don't.
Things I remember off the top of my head in recent years: floppy boot support being removed, pre-ATAPI Matsushita CD-ROM support being removed, stuff like that. Turns out... you aren't going to be running modern Linux on systems that ancient anyway, because the minimum system requirements for just the kernel alone are already higher than machines of that era. So the number of people impacted by those cleanups should be ~0. Are you seeing drivers actively being used by people on modern kernel versions being removed?
You mentioned GPUs, but Nouveau supposedly supports Nvidia GPUs all the way back to the Riva TNT2 from 1998, and the Radeon driver should go all the way back to the original Radeon R100 from 2000. What are these unsupported GPUs you speak of?
Same with RAID cards; I see the driver for the Promise PDC20277 is still in mainline, and that's a PATA card from 2001 or thereabouts.
You can't endlessly upgrade software on ancient hardware; at some point the software outgrows it. Linux has historically been extremely good at keeping compatibility for old hardware, 20 years down the line. No other OS does that. But at some point things do have to go. I don't remember any time Linux broke something within a timeline similar to other OSes' support period.
1) dropping support of some Adaptec RAID cards in RHEL/Centos 8 with Linux 4.18. Like <= 5xxx series. Yeah, Adaptec 5x series is old and weak performance, but perfectly fine and widespread SATA controller card for servers. Many storage-oriented servers don't need anything faster.
2) Radeon RX4xx RX5xx GPUs worked on kernel 4.19, but they don't work for many people on newer kernels such as 5.10 and higher. Lots of error messages in dmesg, lots of reporting on forums, no official guide as to how to fix that. Amdgpu driver is in state of being endlessly rewritten presumably due to shiny new GPU cards and cutting edge Linux can't work with older cards reliably anymore.