Is Linux unreasonable? The kernel has been backwards-compatible to user-land from the start.
Or TeX, C, RS232?
Or TeX, C, RS232?
Maybe at the source level ... at the binary driver level there is no stability at all, and it's a huge reason why the driver scene for linux still languishes in so many areas.
Now there are reasons linux has chosen this model but it nonetheless demonstrates this is not a "free" decision without any consequences.
You are evading the argument, what we were talking about was stability of APIs in respect to the userland code. Linux never promised binary compatibility at driver level.
Also, Linux has far better stability in hardware support than competing systems. If a relative tells me they have a photographic slide scanner or printer that stopped to work with some Windows x.y release, chances are quite good that it is continued to be supported by Linux.
Those are all inspiring examples of projects that went truly above and beyond the norm and achieved great success as a result.