I agree you can "get things done" in any language if you know the concepts. But an expert at a language gets things done in the most optimal way, most rapidly,

I agree you can "get things done" in any language if you know the concepts. But an expert at a language gets things done in the most optimal way, most rapidly, with minimal tech debt. That's all I'm saying and it may be anecdotal but it's been my experience in the industry.