I agree .. this is probably the reason. However I think the fact that dropbox could be utilized in unexpected ways, provided the company with a great deal of goodwill and singled them out as innovators in an otherwise stale market.

Sorry, tried to upvote you but hit down by accident as my fingers are too fat.

They've always had a public bandwidth limit, though, even for paid users.

And this change hardly affects that anyway, except for being an inconvenience.

That seems the likely reason to me.

Because S3 makes a terrible CDN. The latency is bad and can vary significantly.

Using it as a CDN for very large files is fine but for standard static web assets it's terrible.