Do you understand the tradeoffs of why it works that way?

That for an open and fully accessible, decentralised system that exists in an adversarial environment there has to be a large cost to any attacks?

Of course there are much more efficient ways to store data, but those are centralised and vulnerable to the problems of centralisation. The blockchain's and proof-of-work's purpose is to be decentralised.

right. everything is a tradeoff. but in almost every other part of the tradeoff space you can do better than 6 mb/hour for 14 gigawatts.