Hypothetical: as the cost of mass storage continues to plunge, why wouldn’t less-scrupulous states gather as much dirt as possible on anyone of even the remotes

Hypothetical: as the cost of mass storage continues to plunge, why wouldn’t less-scrupulous states gather as much dirt as possible on anyone of even the remotest national interest (through intermediaries, of course), in case it ever becomes valuable? The cost/benefit equation there seems pretty clear. As a competitor state, his much would YOU pay for the next U.S. President’s private Facebook message history? A million dollars? A hundred million? Trade deals in the billions could be at stake.