Note: title should be 'the end of the security-announcements mailing list'. Which is outdated tech anyway...
Yes, mailing lists are clearly out of date; you can tell because they're widespread and actually work, so obviously they need to be replaced with a mishmash of slightly broken alternatives ASAP.
It's also interesting to see RSS touted as a _less-outdated_ solution over email, given the industry has been trying to kill RSS for decades and is far more hostile to RSS than mailing lists.
It would be interesting to know how many actually relied on these lists instead of the customer portal or Cockpit/Satellite to be informed about this.
Google Reader's death certainly was the beginning of the end, and it sent shockwaves throughout.
Platforms like WordPress kept RSS alive, but then you have major publications that redesign and entirely leave out RSS.
Without mainstream reader adoption you have less and less mainstream publishers