[Boldened15]

I would count is as decentralized enough if there are a few major players, you have Google, Microsoft, I assume Proton Mail works fine though don’t know as I only use it for burner accounts, iCloud Mail including Apple’s cool private email relay thing. (Maybe other countries have big providers I dunno.) You can use your own domain and switch between providers if needed, and use custom email clients… it’s all the benefits of decentralization to the end user.