Ruby optimizes for programmer happiness - that was Matz's explicit goal when writing the language. If that doesn't matter to you as much as speed on microbenchmarks, or if writing Ruby doesn't make you happy (it makes me happy!) then Ruby isn't for you.
Consider how many heroku dynos are dedicated to running slow, non-concurrent Ruby web processes, and how many Kilowatt Hours are burned waiting for Rails to apps to start. These are just not problems people need to deal with anymore.
So while I am a big fan of Ruby (I still think it's the closest to my brain's own pseudocode of any language I've used) the ecosystem is lagging significantly these days, not because it's not improving, but because js is improving at a must faster clip.
I can't see how you can assert that the JS ecosystem is "better". It is rapidly changing which is partially detrimental. What worked or was considered a good choice at the start of 2014 is now mostly obsolete or abandoned by the end of 2014.
As so many companies have shown it really does not matter what programming language you use as there are plenty of options to make it work, it's more about choosing the language that will provide the best fit for your business.
This is happening to supposedly mature, nearly decade-old Rails!