idk if you're comparing like-for-like here. I think on EC2, other customers can balloon up to fill your idle time because they're running on the same physical hardware. What this is talking about is renting hardware that is exclusively earmarked for your usage, so your compute is not fungible with other customers. It's more correctly priced against buying your own hardware and maintaining it yourself.
They've tripled on "cloud servers" (shared hardware) as well.