Which is a people problem! The Internet is already a decentralized network. Anyone can hook up a computer to the Internet and others can immediately access it.
Centralization comes from people building bigger and bigger companies which control bigger percentages of hardware connected to the Internet. Consolidation is the natural order of things: competition is hard, so buy your competitor. If you want to solve / prevent it, then there needs to be incentives for companies to stay small, for there to be multiple companies, and for people to (begrudgingly) want more competition. None of this has anything to do with technology.