As surveillance increases the definition of crime will expand.

Consider the incentives. Surveillance is costly. The only way to justify increasing surveillance costs is to demonstrate increasing intervention in criminal activity. If traditional crime is reduced, new crimes need to be introduced.

Once all the enemies of the state have been eliminated, it becomes mandatory to introduce new enemies of the state so they, too, can be rounded up. Eventually there will be no one left to come for and the surveillance technology will go unmonitored.

You may very well be right about the outcome, though I doubt the government cares enough about justifying expenditures to make money the rationale.

In my experience, it's social crises that tend to be used to justify authoritarian power grabs - whether that's a political killing or a worldwide contagion.