Traditionally NIH is the reason for rejecting things. The inverse would be accepting things because they are invented here.

In the early 2000s it was recognized that the C/C++ code-build-run-debug development feedback loop was taking too long for efficient application development. 10-30 minutes to try out changes. It would have been risky not to try something new.

JavaScript revolutionized this, bringing the developer feedback loop time back down to a few seconds. Andrew Paprocki's 2011 JSConf talk demonstrates this. https://www.youtube.com/watch?v=ODgs0eWAIKc

The main competing technology at the time was Lua which would probably have been a fine alternative. JS won. Four years later Node was released which took server-side JS to a mainstream audience and helped validate the choice. Ten years later saw the ES6 renaissance and the rise of JS as a credible language for application development. Now TypeScript takes it to the next level, enabling large robust systems to be efficiently built using JS.

I'm pleased we bet on JS.