[quesera]

I agree with your larger point, but FWIW your example does not match my experience.

I've never had any special difficulties hiring Ruby/Rails devs. Quality is high, availability is reasonable (hiring is always something of a struggle!). My first Rails hire was in 2003 (rails-0.8, IIRC) and my most recent was about 6 months ago.

That's 17 years, and counting.

OTOH, I've never had a good time hiring people to maintain EOLed apps. Ruby or otherwise. "Sustaining Engineering" is a (misnamed) trade that isn't as broadly attractive as new development.