He meant GLibC function, not syscall...

It's not alien, it's solid engineering. Further, it takes attention to detail and work to maintain ABIs, which can be boring and unsexy - which is not what a lot of evening/weekend hackers are interested in. So likely most of this work is being done by commercial distros in response to customer demand.

Further, even for the API, there are ways to offer multiple versions of those. You can categorise your APIs in various, including with levels. Applications can then *choose* to explicitly depend on certain APIs or they can choose not to and use whatever the default API is - some applications will do that through laziness or ignorance.

All boring and hard engineering work, but it's what widely deployed (in space and, especially, time) systems tend to have to acquire.