Julia and Mojo are attempts at solving the "two language problem", which not every Python user actually has -- they're fine doing work exclusively in Python, not even using any of the libraries you're talking about.
replyMojo in particular recognized to compete with Python they'd have to be a superset, then they backed of that goal when they realized it would be too hard.
So at the end of the day, Python has a value proposition and it cannot be entirely subsumed by other languages, because those languages make tradeoffs that move away from Python's value.
Python's value is being a portable scripting language, a better Perl, unfortunately some try to do full blown applications with an interpreted language.
replyPerhaps it's worse that some even succeed in building very complex systems that can handle a lot of load too (see eg. Instagram)? ;-)
replyPython has a known set of trade-offs, mostly related to loop performance. But if you understand the trade-offs and available mitigations, it should not stop you from building good software. You know, just like any other ecosystem.