One thing you'll run into with rails in 2018 for web development is it's going to be hard to find developers and only getting harder by the day. Rails developers are aging. They are no longer your 20 year old hipsters, that stereotype has long since gone, they have families now and boy are they EXPENSIVE. React is what people new to web development are LEARNING and that's all you need to care about. You can get react developers, who can fundamentally produce the same thing (your run of the mill CRUD apps), for a lot cheaper and they are (more) readily available. Anyone who claims that rails does something magic the others don't do by now is showing their allegiance rather than making a factual technical statement.
In a few years I expect the problem to worsen as react chips away at rails, and with no standardized reactive SPA (maybe save for ember), more and more developers who aren't die hard rails/ruby guys are going to be rebranding themselves, who will then be in the pool with the rest of the react developers, which, also seems to have crossed an inflection point recently.
I also encountered a few guys who had rails experience but wouldn't take the job because they didn't want to risk falling behind on react. Sad but true.
This post isn't supposed to come off as agist, its just an observation when working in a tech field that is largely driven off fashionableness, trends and approval, rather than strict technical merit.