You filter 95% of such emails sent to you, which is trivial but important. If you're accurately reporting your filtering behavior (it is no slight to say that people misremember things all the time), sending you email is stupendously profitable. It just means it (statistically speaking) costs about 20 cents to hit your inbox instead of 1 cent.
Your behavior is not normative, though. Even for very techy audiences, a lot of people actually enjoy getting email. We can know this with certainty because they will open the emails, they will click on things in them, and then they will buy when you tell them to buy. Insert NDAed anecdote from Client #1, NDAed anecdote from Client #2, and NDAed anecdote from Client #3.
The lady sitting 20 feet away from me in this coworking space runs a less lucrative business than most enterprise software companies, and individual emails have earned her more than BCC has earned me in the last year (at approximately the same number of people on the email list).
The focus of my work for WPEngine this week was designing a marketing product for them and making a drip mail channel to send eight emails in the month after someone uses that product. It should absolutely print money. (One penny to send an email, use your imagination as to what a $200 a month hosting account is worth.)
Hopefully, WPEngine will let me talk about it after we have good stats.