I think it's worth separating what IPFS provides from what Filecoin offers (note that I work at the Filecoin Foundation/Filecoin Foundation for the Decentralized Web, but I'm hopefully being sufficiently technical here that the description is as objective as I can be.)

IFPS is a model for providing a content-addressable storage system -- so if you have a particular hash (the CID) of a piece of content, you can obtain it without having to know where or who (or how many people) are storing it. Obviously one site on the IPFS network you're using has to have stored that data, but it only needs to be one site. More sites make it easier and quicker to access. Almost all IPFS nodes are run and offered for free, either by volunteers, major services like Cloudflare or Protocol Labs' dweb.link (which act as gateways so that you can access that file network over http/https) or web services that you pay to host your content on IPFS and manage it through a traditional API, like Textile or Fleek, or Fission.codes.

The key point here for someone with your use case, is that you have lots of flexibility as to who is hosting your files. You can start off just running your own node, or pay someone else, or pay lots of providers that are geographically diverse, or just do it among a bunch of volunteers. You're not tied to a single provider, because wherever your data is stored, you or your users will be able to find it.

Filecoin is a project to fix the incentive issues that can affected historical decentralizing projects like bittorrent, and can lead to decentralizing attempts like this collapse into just a single centralized service like AWS.

Storage providers on the Filecoin network negotiate directly with customers to store files -- they receive payment directly from those customers, but they are also incentivized to offer storage, and also store those files over the long term, because Filecoin has a proof-of-storage setup where storage providers get utility coins in return for proving that they're either making space available, or storing customers' files. It's all very zero-knowledge-proof and fancy, but the important thing is that with this in place, and a flat, competitive market for storage, storage provides on this network have good commercial reasons to offer low prices, and don't care if you're not tied directly to them (in the way that Amazon and other traditional storage providers are tempted to lock you in.)

Filecoin isn't so much a derivative of future declines, but a way to establish pricing in an environment where there actually is a free(r) market for online storage. And IPFS is a protocol that establishes one part of that freer market, which is to decouple who is storing your files, from how you might access them in the future. So far, this seems to be working, with prices being much cheaper than the alternatives, and with some degree of geographical and organizational diversity: https://file.app/

Storage providers are also now also competing on other aspects, such as ecological impact (see https://github.com/protocol/FilecoinGreen-tools ), speed of access, etc, which is what you might expect in a flatter market. We also see larger storage providers providing separate markets for large, >1 Pebibyte customers.

Happy to talk about this more, I'm danny@fil.org. Big fan of your work, etc, etc.