(Yes, I know they're for-profit companies who have every reason not to want to relinquish any control over their network. Doesn't mean I can't hate on them for not even pretending to support consumer choice.)
By my way of thinking, your choice of language (not because of you, the person, but of how the words have become ingrained) is indicative of the problem: "consumer" versus "customer." We consume what the various companies choose to offer to us in the way they offer it. We are not treated as customers, valued or otherwise, in a competitive landscape. There exists a one-way flow, from the company doing the advertising to our eyeballs to consume it.
Look at the businesses people claim to like: local shops, service providers like Fastmail, and the like. In those cases the people giving them money are treated as customers who have other choices and who have made the voluntary choice to continue to associate with that business.
That's what is missing. Customer instead of consumer.
Of the rest, more than half host their own MX. While that's totally reasonable, it means the percentage of people willing to pay just $3/month to be a customer is even smaller than it seems. And $40/year is the cheapest that one could ever hope "being a customer" would cost.
So, lots of people say they want to be customers, but even when doing so is close to free, very few actually do.
(Nothing wrong with using Google because it's free, only while concurrently claiming to want to be a customer. I agree with your point and I'm a happy FastMail customer. I'm amazed FastMail can make a profit at $40 and it's a huge credit to them that they can.)