If everything is completely decentralized then it essentially means that each person is providing for themselves… including basic services like water and waste processing. Centralizing these things makes sense, they’re more efficient when operated at scale, and there are significant benefits to task specialization. And frankly, you don’t want decentralized medical care - you want big, modern, well-funded hospitals with the latest technology, which means centralized locations and management.
Decentralizing services doesn’t make sense. Individual residence solar panels are substantially less productive than large-scale solar plants. Services like energy, water, medicine and waste handling should be concentrated and publicly funded - but then that means you need to collect public funds and then decide how to use them, and that means government. The larger the public project is that you want to build, the larger the government around it has to be.