I understand this thought for external dependencies, but dependencies also includes internal ones, which I don't see a reason to reduce. Modularity and re-usability of individual pieces of code are a good sign for me.
Dependency managers like NPM don't differentiate between internal and external dependencies. I assumed that the Svelte devs were referring to this. Vue for example only has internal dependencies, but NPM shows them as any other: https://www.npmjs.com/package/vue?activeTab=dependencies