While I do agree that your approach leads to good result, I still don't see why you wouldn't add a compilation step to minimize/tree shake/TypeScript/etc.

If you're good enough to be conservative in what you pull in, you'll still be that, except you get to benefit from all the things a compilation step can offer. It still strikes me as a somewhat arbitrary limitation to impose on yourself.

I use webpack for almost all my projects, and TypeScript for a bunch of them. I'm also very mindful of what packages I use and the result is nice little bundle. I wouldn't be able to get the results I want if I limited myself by not having a compilation step.