[Someone]

Very recent? 2006, according to Wikipedia (https://en.wikipedia.org/wiki/RubySpec). That makes it about half the age of ruby.

Worse, Wikipedia claims

"The RubySpec project was discontinued at the end of 2014 due to a lack of uptake from mainstream ruby developers"

[riffraff]

I don't understand what you're arguing against, given your own words say it didn't have uptake (in MRI) till 2014.

The project has been revived and adopted officially by MRI only in 2015. http://eregon.github.io/rubyspec/2015/07/29/rubyspec-is-rebo...