TTY's choice of eliminating dependencies is short-sighted. By embracing dependencies, a library can be more powerful, have more features, solve more problems.
Thank you for pointing me to Perl library. The only thing I would say is that TTY gem does not have option parser and will probably not have one. Its main concern is more focused on prompting for values than actually providing a way to structure command line interface. There are already libraries that do an excellent job of that. Other features I will have to look individually into. I'd love to have more input on that from yourself.
I have actually recently thought about the dependencies for this library. Originally I wanted to make it easy to vendor things but I have actually started extracting code from this lib as well. For example, the https://github.com/peter-murach/equatable library. So I definitely agree with you and think this is the direction I'm gonna go!