I think the advantage is that it's easier for _anyone_ to be able to keep a site/file alive without having to implement an archive.org style of rewriting all the URLs/links. If you want, you could pin that medium article you talk about and now even if the medium node(s) decide its no longer worth pinning, you've still got it pinned so it's accessible to anyone at the expected "location".

Similarly, this makes take-downs harder. It's no longer one node/machine hosting a file, but as many nodes as who find it valuable.

If users never pinned anything, you'd be correct, it would be basically the same as the current internet, with one organization maintaining everything. But IPFS gives you the ability to change that.