Your arguments are more philosophical rather than technical and real. If we start going down that path we would soon realize that even your being is not decentralized simply because you can philosophically argue about anything and bring reasons why you found truth where there is no facts.
Indeed, you are correct.
But consider the situation where crypto more or less takes over, and tyrannical leaders use regulation, ISP's and controlled infrastructure to block the whole phenomenon to keep control over the population. Wee've seen it in several countries already. I believe it is a discussion that needs to be had, not least including people much smarter and more technologically experienced than me.