I would disagree with the final part. Freelancing and actually earning a first-world developer income successfully requires quite a few skills that aren't part of a typical development job.

Knowing where and how to find leads, how to convert them into prospects and clients, how to negotiate, how to scope out a project, how to appropriately push back against scope creep and how to manage a pipeline of future projects are all important skills if you're freelancing (and not using a "race to the bottom" platform).