I take the opposite (hipster) view. If a language is suitably popular it's because there is something bad about it. Either
A. the barrier to entry for other languages is too high (Javascript for the browser, Objective-C and Swift for iOS, etc), and so there is no evidence that there is anything good about it (you just lump it and accept that's the way things are done).
or
B. Because it is still a generic, C-style, imperative, possibly somewhat OO language that feels very similar to a language you already know, and which is a reasonable choice for nearly any problem (rather than ideally suited to a subset of problems), and you are probably selecting it based on that merit rather than any real technical merit the language offers. (Note that this can be a reasonable business decision, but oftentimes people delude themselves. "We use the best tool for the job"...so long as that tool is Java or Javascript)
As you say, all imperative and OOP languages are fundamentally the same; for me it's when languages veer off that path that they start getting interesting and really differentiate themselves.
As a note, too, 'there is no easier way to create a single GUI for 3 platforms, as JS' is not a testament to how good JS is, but a testament to Netscape being in the right place at the right time. It was a language written in a week, whose syntax was forced by suits to be 'Java like' because that was what was popular at the time, and which had no competition.