The Ministry of Truth simply doesn't want unaccounted and uncontrolled snapshots of history. Too much hassle steering the narrative regarding any surfacing truth-now-meant-to-be-lies and vice versa into fake news territory, discrediting by association, cranking up troll farms.. Much easier to make this inconvenience disappear with the due cooperation from the controlled outlets of information.

Then they will come after our local storage, and making it prohibitively expensive is the least malign way they can come up with.