But if Walmart has a monopoly over certain goods, it is more than an inconvenience to be banned from Walmart. If your email server cannot deliver mail to 25% of all active email addresses, that's more than an inconvenience.
We can quibble about semantics, but those examples are not caused by centralization.
Yes, any company can take advantage of their position to influence the market, and in most cases this is illegal.
If a manufacturer only offers their products in Walmart, and some users can't access Walmart, then that's a problem specific to that provider and manufacturer. And the same applies for Gmail. *This is not because decentralized protocols "trend" towards centralization.* It is because there will always be popular providers that people gravitate towards for whatever reason. But again, this doesn't prevent anyone from using email without depending on Google _at all_.
The difference from that situation and issues caused by actual centralization is night and day. I'll stop replying to this kind of rebuttal, since it seems people struggle to understand the difference.
