I could buy that reasoning in the 90s. Heck even in 2000 after the dotcom bubble burst. I could maybe buy it in 2010 although by then networking was in no way even remotely niche. We’re now into the third decade of networking and far less important additions to the standard library have been made.

A TS is almost nothing in the c++ world. Each implementation will have its own quirks and unreliable cross platform behavior if it’s even available. There are well established filesystem libraries too (heck the STL implementation is almost identical to boost for that reason to make it easier for those people to port and for the library maintainers you basically just wholesale copy an implementation or at least have a reference one to test most things against).

> Also sockets are arguably an outdated networking model anyway, so people really serious about high-performance networking will be doing their own thing regardless.

I’m eager to hear what you mean by this because I’m unaware of any OS APIs that do Networking in any other way. Unless you’re talking about userspace drivers or DPDK, neither of which see serious adoption outside of data centers (if even there). 99.99% of an networking code I’ve observed across mobile and cloud is socket-based.