Who takes up most of my time, as measured by the number of words I've written to them? Who is worst at responding to me? Can you do anything with sentiment analysis?
Besides the obvious gmail, I think your fundamental competitor in the not-gmail space is fastmail.fm or something like it. If you think you can make a go of it at those prices, plus or minus an order of magnitude, then have at it.
Mail is not for the faint of heart. Besides the technical details (which are harder than most people assume), you have to operate in a way that you earn and keep the trust of your customers. You have to not lose mail, you have to stay up.
You have to accept that you'll be an unwilling partner to the NSA and other law enforcement. You'll also be a target of under the table surveillance by the NSA and other spies and criminals.
You have to get email fundamentally, rock solidly right. Above that there's lots of room for features and services more or less related to email.
You're going to have to work hard to peel me away from fastmail, and you'll have to work even harder to peel everyone else away from gmail, or even to get them to notice you.
I look forward to your Show HN (truly).
That icelandic one from recently (forgot the name) I can not take too seriously, since they want to roll their own browser that will basically be a bad version of Tor browser and also some other stuff they want to build their selves.
[0]: https://mailpile.is/
Many people on HN probably either host their own email or considered it, but a good secure service is better to sell to people without that technical knowledge who don't want to be a Google/MS/Apple/Yahoo/etc product. I've pointed less technical people towards MyKolab before; they are a good model for how an email service should be done.
Hmmm, there's an interesting idea for a business, Back End As a Service. You provide rock solid email back end, and your customers are email "providers" who distinguish themselves on features, price, charity, whatever, all of them using your back end services.
And that, my friend, will occur for as long as a million human beings are born each day.
If I had the slightest inclination to make a mail service I would buy this name, but I don't, so have fun.
https://www.minervafabric.com/
Feel free to ping me for more insight or specific data.
Imho, it's extremely hard to beat what Google offers.
lots of storage / archive
contacts / sync
kalender / sync
decent privacy/ encryption
servers in EU
i dont care about webmail/mailclient.