We announced this publicly so that you now know: if you write on Svbtle, your content is vastly more likely to survive for a long time than if you used your own server (probably) or if you used another publishing startup.
Anyways, I think that it would have been more effective if there was an actual plan associated to it. For example explaining that all the static content is stored on S3 and there is money set aside to fund the static serving for 5 years. And that users can get a dump of their website for after that period.
I had to chuckle.
I'm thinking something on the level of changing into a non-profit organization with a backing trust to support the continued existence and maintenance of the product. Similar models have worked throughout history, and it would be ground-breaking to do something similar for the concept of digital content.
(Edit: apparently this is what Posthaven is trying to do, and has taken steps to at least attempt to set up. Sounds difficult!)
You could even set up a separate legal entity that would have a trust set up to keep these backups alive, or partner with e.g archive.org.
Edit: looks like you're already doing something like that :)