So that any user could install anything they wanted and use it as they wish. Including replace components with similars and/or make modifications.
I think this is reasonable.
It's unreasonable to expect companies to support old products indefinitely, otherwise they would collapse under the weight of the legacy.
It's also unreasonable to leave customers that bought something, however old, with nothing to fix it themselves.
Ideally also the companies would have to release all this at least a year before EOL for people to be able to get acquainted with the codebase.
Beyond that, as an example, open apis (for drivers re:hardwwre) are not the same as giving full chip scematics.
But! If the, for example, SoC stopped updating binary blobs, and things stopped working with newer kernels, as an example, then they'd have to 100% open up and provide sources.
People get all rah-rah about the environment, but I throw away pounds and pounds of highly polluting electronics, just so someone can sell me another.
This model need to stop.