I know libraries and museums are full of oddball things like wire recorders and wax cylinders that are used as examples, but I'm just not sure that's applicable to most (not all) digital files now. I just can't imagine there will ever come a day where we'll say "It's time to convert these 1 billion PNGs we have saved to the latest greatest format or we'll never be able to use them". Hopefully I'll be alive in 30 years to see if I'm wrong :-)
Digital data formats have the same problem as large and popular websites (eg. social media): they look permanent, simply because they're so popular, even when they never are really permanent. At some point, they're going to fall into disuse, and from then on, documentation will slowly fade away.
This is why it's so important to work on permanently documenting these file formats today, while the 'documentation rot' is still fairly limited. It's why things like this exist: http://fileformats.archiveteam.org/wiki/Main_Page
I don't think it's overblown. I think we recognized an upcoming problem and some of us made efforts to mitigate it. We still couldn't save everything, but like extinction, is difficult to prove.
Concerning hubs: There are hublists, which include open hubs; but don't except quality and safety there. Most great hubs from the past went off the grid at least a decade ago. To go there, you need an invite. You also need to obey to draconic rules, like 24/7 uptime or 6 TB min high quality share.
I find it very important that people keep this stuff around, the internet forgets so easily.
