Utter nonsense. Whilst Ruby/Rails may no longer be cutting edge Indeed.com/USA currently has 302 Rails jobs by title search compared with 567 for Node, 204 for Django and 142 for Laravel. That's a long way from the “COBOL of Web 2.0” by any stretch of the imagination. Rails also maintained a high score in the review of last year's Who Is Hiring:

https://letstalkalgorithms.com/analysis-of-2018-hacker-news-...

As for Ruby outside Rails, have a look at Metasploit, Puppet, Chef, ROM, Rhoda and dry-rb to name just a few.