Agreed. Except your first rule (A) is broken. We make lots of money off hackers & developers. It's time to retire that old saw that "developers don't buy." They do, lots of them.
I should have qualified that statement. I have no personal experience selling to developers and I think many of things I listed in (B) are either harder or impossible to sell to developers.
Because hackers/developers work at a lower technical level than others, they usually don't need niche web hosting ("I'll just spin up a Linode VPS"), web publishing tools ("I'll just hack together the HTML/CSS myself"), or SEO guides ("I'll just search HN for SEO tips").
The companies that successfully sell things to hackers do other, specialized things (think GitHub, Linode, Stripe, etc.). You don't make money selling any of the items I listed do you?
