This is a very fair answer, and all "permalinks" are lies. At the same time, I wonder if it might not be possible to have snapshots up on, I dunno, IPFS or torrent sites or something such that when the unavoidable happens, not all is lost.
If the concern is perpetual access to archived content but under your terms, that is where the cost comes in. Somebody somewhere is paying for power, cooling, connectivity, and disks. The Internet Archive estimates it costs them $2/GB to host data uploaded in perpetuity. Please consider donating if you're uploading content for permanent archival and/or deriving value from hosted content.
ipfs's economically incentivised hosting layer (filecoin) offers storage in monthly increments, not perpetual.
practically yes, but
A system of mirrors prevents a single node going down from taking the whole system (in theory at least, we've all seen plenty of times where failover goes poorly), but it doesn't do anything to ensure the long term survival of the system as people lose interest, lose the ability to participate, and sometimes die.
If you were around certain internet forums in the late '00s you might have run in to an image hosting platform called WaffleImages which was created in response to yet another popular free image hosting service locking down their embedding and ruining thousands of old posts. The goal was to distribute image hosting among community-operated mirrors, and it worked great for a few years. Over time though people lost interest while the rate of new mirrors getting added dropped to basically zero and eventually it fell apart.
Cool URIs don't change: https://www.w3.org/Provider/Style/URI.html
You can believe that cool URIs don't change or you could go the IPFS route. Similar to the way torrents have a 'health' score of plenty of seeders, and IPFS resources could live as long as people want that resource to exist (Not sure if that situation is baked into IPFS though).
Also: have you looked into Filecoin?[0]