What "new hot JS runtimes" are you talking about? Node has been pretty stable for over a decade and a half. This is the first time that anything is even challenging that place. It just so happens that both Bun and Deno efforts started around the same time and now have to compete with each other

I think any competent company would be savvy enough to avoid lock in for a technology with adoption this low. I don't think that's what these features are aiming for. I think they're aiming for the young dev starting side projects that wants to get up and running quick. Or imagine teaching a bootcamp class and you want a tool that will do some magic for you so you can focus on explaining other complex aspects of web development