And there are many of them, some owned by companies that use them exclusively, some conglomerations of many different providers but owned by yet another party. How is this centralization? I still think you're just arguing that we've compartmentalized certain services to sets of companies, for the most part, but even that isn't centralization, because there are multiple distinct companies using multiple distinct networks and in many cases they are presenting multiple distinct capabilities. Not having something handled at the end point does not mean it's centralized, there's a very large middle ground here, and that's where we are currently at. I'm not sure I see any evidence that we are moving away from that towards actual centralization.
> When I received mail in '95 or so the machine receiving it was the workstation I wrote the reply on.
And many people that used POP3 continued to do so well into the 2000's. It's silly to run a mail server on your workstation. I know, I did it for years myself. You run into all sorts of stupid problems related to your workstation not being always on, badly configured backup MX servers, and other issues. We don't do it anymore not because we were forced out of it (you can still do it now), but because there are solutions that are better for most use cases, and we opt for those.
We don't all wash our own cars, or do our own plumbing, or even clean our own houses. Some people do, some people pay others to do that work. The fact they pay others doesn't mean we've moved towards centralizing those services. There isn't some national bureau of plumbing that is our only recourse when the toilet is clogged and we don't want to fix it ourselves.