This is the best place for this kind of feedback/recommendation!
I think part of this is that Discourse was never meant to be an email marketing platform, so you’re right that it wasn’t built with marketers in mind. Generally emails sent from Discourse are transactional, and directly relate to an individual’s activity in the community.
Discourse will never be good as dedicated email marketing platforms are at sending marketing emails, but additional email functionality isn’t an uncommon request. It’s likely that any marketing-related email improvements will rely on integrating with third-party services (something we’ve started to look into more recently).
Some integration with third-party emailing services can already be achieved through webhooks, but those can be hard to approach if you’re not technical… and even then you’re a bit limited.
What future improvement will probably look like is a more direct integration with email marketing platforms like mailchimp, convertkit, constantcontact, etc… So it’s possible you may be able to configure some simple no-code automation like:
if [user hasn’t logged in within X days] then [subscribe user to X mailchimp list]