I don't see how it is a good thing for things that haven't been adopted to make it straight into the standard. What's wrong with publishing libraries, then standardizing the ones that are already de-facto standard? Github makes things super easy, publish stuff, and in a few years we know what's what and then standardization is a simple nod from the committee, reflecting the reality of what's already used in practice.
I don't know where you're getting this from. Ranges has multiple implementations, and has been on github for years. Dalton's been putting together his framework in public on github, seeking to bridge LLFIO/ASIO/etc with plenty of stakeholder feedback. Elias has had his library on github for yonks now with plenty of users. It's not as old as fmt, true, it was designed to do the inverse of fmt in a similar way. Zach has had his Unicode library on github for years now, indeed it's even in Boost format with a fairly complete set of Boost format docs. LLFIO has been in public view since 2013, underwent a review here in 2015, was completely rearchitected based on that feedback and has since gained a good few number of hardcore users. Now, I'll grant you that none of these are ASIO-type popular libraries. But it's not like they lack implementation and userbase experience, either. Most of these are multi-year old codebases with real world users using them in production, and giving ample feedback rounding off the rough edges over time. I'll put this another way: there are plenty of standard library proposals before the committee with no reference implementation library whatsoever even attempted. There are lots more where the reference library was clearly thrown together so there was one at all, and nobody actually uses the proposed library in production. Nobody can say that about any of the libraries above, bar perhaps Dalton's, and that's only because he's implementing a recently begun feature discovery bridge between Ranges i/o and everything else. I would agree that there is insufficient user experience of these libraries yes. They could do with more. But I'd also argue they're in the top 5% of standard library enhancements being currently proposed for standardisation in terms of real world use experience. They're good, relative to what else is being proposed. We live in the world we are in. Niall