None of the sites you mention above would require npm to build.
At some stage after you've seen enough 'interesting' dependencies changing the world around your app as you write it you'll realise that boring is good for most of the tech you depend on - the more boring the better, and the fewer dependencies the better.
At some stage after you've seen enough 'interesting' dependencies changing the world around your app as you write it you'll realise that boring is good for most of the tech you depend on - the more boring the better, and the fewer dependencies the better.