I agree, that is slower than the internet connection at my house, which could just host a few TB of spinning rust attached via USB faster.

Before I moved to backblaze I was half seriously lining up a few friends to share a similar setup that would self replicate between our houses and provide a simple restic interface.

Besides, they do charge for egress over a certain threshold so it seems they are also capping how much they can make from some customers. I get that there are probably a few problematic ones, but it seems that the business should be able to figure which ones are causing problems and solve it that way, rather than punishing the smaller customers using them as a storage depot. Customers whichh go years with a low level of upload+transactions under the theory that should the need arise the entire repo can be pulled back down at a few hundred MB/sec in a manner of hours.

"and they're not even reasonably cheaper than the competition."

Such as?

Cloudflare R2 seems designed for migrating off of someone else