Maybe you can move on, but there is srill, and as far as I can tell will be for some time, a need for knowing how to work computers in exactly the same ways that were necessary in 1970.
Embedded systems programmers probably know all about characters, arrays of them, pointers to anything never mind null terminated strings and so forth.
It is good that some ppl can still be bothered. I don't use libraries much because a certain kind of fun is owning the metal.
And if the pros who know get the big bucks, that is fine with me.
I'm not aware of any other option that was not mentioned in this thread, at least for small controllers' memory. Basically, these are the options that you have. Please, let us know if you find something better. Well, you can also just take one and add the functionalities that you need, its free software ...
You don't have to, if you use a system that is 50years more advanced than the CPU that C was originally developed for.
But you know, an AVR is really close to a PDP-11, especially WRT the total code space available, so I don't think it's surprising that we're stuck with functions from that era...