Imagine everyone was happy with C/C++, we wouldn't have Rust or Nim. Imagine everyone was happy with Java and JavaScript, we wouldn't have Dart or Go.
The most used programming languages today are JavaScript, Java, Python, PHP and C++, all of which are shit-tier. We definitely need more languages, not less.
If we have good languages, the ecosystems will develop around it... it may take 20 years... but I think it would be so much nicer to see a new much better language have a great stable libraries in 20 years... than people still having to deal with shit-tier languages like python and Java in 20 years.