You may want to write that, but why would someone want to use a database that could be 50x faster if it was written in a native language? If you write software for yourself in a slow scripting language, that is one thing, but it leaves a huge amount of performance on the table.

This is the same as the problem with electron. People that only know javascript might think it is great to embed a full web browser, but it is selfish to users to push something that they think will run at a normal speed only to have it use 100x the memory and lag during simple operations.