Paying some pinning service is, architecturally, not much different than paying S3 to store your files.

Filecoin turns file storage into a marketplace, which is a significant improvement. Currently S3 charges a large premium because you wouldn't trust many other people to reliably hold on to your data. I expect this will cause the cost of file storage to plummet.

Your venture capital heuristic is a good one, but I think the rest of what we know about Filecoin overwhelms it.