I agree that "+" looks better than ".plus" but this is a matter of taste (hello Ada).
Yes, I use Scala at work but I can't call myself a seasoned Scala dev, true. On the other hand, just every expert in this or that language will always have a counterargument for you and a solution to the problem. Because he IS an expert! The thing is, not all people are experts or even will be. Most people want a tool that doesn't get in your way, easy to pick up and deliver the results. That is why Python is so popular despite being slow, inefficient and basically a glue for C/C++ libraries. Hell, even for interfacing with C Python loses to Lua. But all these shortcomings didn't matter in the end. Python2 → Python3 didn't kill the language either. I am afraid Scala's error margin is not as big.
And yeah, you are totally right. Most people indeed choose the way of the least resistance and don't want to spend much time learning a language - for good reasons. Scala will never be as popular as Python or Javascript. It is a language for people that are ready to invest more time and dedication to get a higher productivity after some time. Not everyone wants to do that and many people find it too hard. I think the Scala community knows that. :)
Yeah, Scala makes it possible to write cryptic DSLs. I just don't use libraries that do that, but there are not many such libraries anymore anyways, that was mostly abused in the early days of Scala. Now, 15 years later, that's almost non-existing anymore.
But not having symbolic characters in method names is just horrible. Here is Java code that calculates some datetime:
Here is the exact same calculation, but with Scala's "symbolic" characters: I don't need very long to know what I find far more readable ;)