I don't know how you call that decreasing or flat, I'm seeing up and to the right.

on HN trends up to 2012 it was about the same as python or sometimes higher now Ruby is way below. The general trendline of up is the result of HN's Who is hiring thread popularity and increasing number of job posts in absolute numbers. Here it's more evident, Ruby was the most popular language 3 years ago http://www.ryan-williams.net/hacker-news-hiring-trends/2015/...

I agree that proportionally it's less but it's still growing