Right, but we're comparing languages, not their ecosystems. It's not a language's fault if the community hasn't yet realized it is better for some purpose and overcome the market effects of tons of existing packages already being in the popular language by migrating them to the less popular language. This is simply using inefficiency as a justification for subsequent and ongoing inefficiency. The whole point of an argument like this is to compel people to put effort into porting things out of a sub-optimal ecosystem.
In the short term it is of course convenient to just use the most popular thing always (in which case we'd all still be using PHP and Flash), but eventually things do switch on a large scale, and it benefits all of us to push this along when we can.
The more we double-down on an inherently sub-optimal ecosystem, the more we are trapped by it.
Imagine if all the effort making Python usable over the last decade had instead been spent on giving a compiled language better dev UX and GPU support...
I'm not even a fan of Julia, but I probably would be if it had received the same attention Python has for the last ten years.
Conversely, I'm _still_ not a fan of Python, even after all this time and effort has been expended, because the foundation being built upon is just simply a bad one for high performance and high security domains. Anything they manage to get working is akin to a hack, and is working in spite of the language in which it is built.