Deno doesn't need to solve for this, it's already achieved it. An interpreter has nothing to do with a package manager. One problem that Deno is actually solving is the tight coupling of NPM and Node. Commonjs is very much purpose-built for NPM modules.
It's a smart call for the team to tackle this problem as it's one of the biggest pain points of using Node and the biggest threat to its long-term sustainability. But I fail to see how no package manager is a viable solution. As someone who's used Go and Node for the majority of the time they have existed, trust me when I say that a package manager is a good thing.
Node is an incredible ecosystem. We just need a better implementation of its package manager.