Why is it 'clearly' on its way out? IMO Rails is still the best web framework around, and the last release has really put it ahead of its closest competition.
I can't speak to this. I'm a Go and Python programmer. I learned Go in about ~8 hours and have been very productive with it over the past 2 years.
I've been struggling at work to learn and use Rails for the better part of a year. I constantly have to grab someone and have them help me. Either I'm an idiot, or Rails has a bigger learning curve than people make it out to have because I've never experienced this in all my 10 years of programming professionally.
Ruby is too forgiving, has multiple syntaxes for the same thing, and lets people do really obscure shit in a large codebase (monkey patching, hidden imports, etc). In short: it enables developer laziness.
I've found Ruby code the hardest to debug over the years. Also, I think the web development community is waking up to the value of type safety.
I will use Ruby for the occasional script because I like its backtick syntax for invoking other commands, but that's it.