IPFS is not magic: it runs on servers and people have to pay for storage and bandwidth. If you're not regularly paying those people, your content will disappear unless it's among the most popular and not legally encumbered.

If something is taken down for legal reasons, you're left with intersection of hosts who are in legal jurisdictions where they can blow off those complaints, don't have their IPs blocked, and are willing to host it for whatever you want to pay.

That's not impossible but it's far from the solved problem NFT salespeople present it as, increasing in difficulty with the value of the content.