We’ve got three operating systems, three giant cloud providers, and a near monoculture of browser engines. It’s not great, even if it could be worse.

Internet is quasi centralized already. An outage or intentional disruption by a couple of companies under US Jurisdiction can disrupt global internet. Yes you would still have some clustered connections here or there but most of internet infrastructure is almost centralized already.

Telecom providers of various kinds are responsive to governments so I'm not sure that it "isn't" centralized as far as the ability for bad people to do these things goes.