The web tooling that exists in the Node ecosystem is hard to reuse elsewhere.

I’ve stumbled over this while working on Nanoc: it’s tough to have an asset pipeline that deals with JavaScript and CSS and integrate it nicely. For Nanoc, it is often more reasonable to let Webpack/Parcel/etc compile into Nanoc’s content directory (input for Nanoc), and thus have a two-stage process. Still, not a great solution because the two seem so disconnected.