Ask HN: Why is transactional email such a mess?

Providers recommend reliable providers like sendgrid, mailgun etc and they don't have a good pricing to start with and don't want low volume customers. Sendgrid automatically closed my account while signup and send me some email with violation, even though I never used it before. If I am not on AWS are there an alternative which are considered reliable yet not from the so called reliable providers ? Can a developer not reliablity run own SMTP server ?