What makes the libraries blessed by the language designers so much better than a library blessed by any other trusted party? Rust is an open source language, and only the core team works on it full time - even then, any one of them could leave at any time and the community at large would need to pick up the slack. This isn't any different than the situation around any of the amazing community libararies in the Rust ecosystem. Heck, libs blessed by the language designers aren't even always the best choice - just look at json manipulation in .NET; you get multiple different stdlib ways to work with json, yet the community still gathers around the much better JSON.NET package.
In terms of value proposition, I think the author is just hankering for some .NET style support agreements in order to hedge his maintenance cost bets - and I'm sure there are or will be plenty of consultancies willing to provide this service, so long as the demand exists. That open source language users are entitled enough to expect this service for free from language maintainers... I'm not sure that's completely justifiable.