If you're working freelance, as a consultant or building a product, people are paying you to spare them the technical details. They don't care what language you claim to be a guru in and you shouldn't shoe horn in your preferred tech stack when something else is more appropriate. Also, if you frame yourself as just "an expert in language X", you're only setting yourself up as a replaceable commodity.
I think having the skills to understand business goals combined with the ability to design and develop solutions where you're flexible about what tech stack is used is much more valuable to businesses.
Also, I don't understand the false dilemma of having to choose between being a "jack of all trades and master of none!!!" vs "super guru in one area". It's very practical to get to expert level in several languages and frameworks, especially given the similarities between many of them. If you spend all your time on one language/framework, you're going to quickly reach diminishing returns in terms of what you're learning vs how useful in general it is.
How much better are you really going to get at Python after spending 1 year, 5 years and 10 years with it? Surely at some point you're just learning obscure tricks or the ins and outs of libraries that are going to be outdated in a year or two anyway? Why is that valuable compared to being more well rounded and learning transferable skills?
If someone has been programming for a long time and they only list they're highly proficient at one language, that's a red flag to me they lack perspective and are unlikely to be able to architect solutions that require the bigger picture.