I would also say library quality can be generally low. E.g. there are numerous flag parsing libraries but not a single one comes even close to clap in rust.
On the other hand, I find it sad how terrible stdlib's flag library is. I'd love to have something like Python's argparse, which is not perfect but enough for most of the time. Go's flag doesn't even work well for small programs. It should've been more like spf13/pflag, but as we've often seen with Go, they went "screw decades-old conventions" and did something strictly worse.