>10Gbps being uploaded 24/7 to the cloud

that might seem a lot if there's only one server, but it's really not that much considering that it's going to be uploaded from multiple precincts. Wikipedia says there are 21 "districts", so that works out to a 500 Mb/s link per building, which seems pretty modest for a institution.

>20 petabytes stored at any moment if you're holding everything for 180 days.

If it's being stored using aws glacier deep archive, that's only $20k/month. That's probably a drop in the bucket compared to the rest of the costs associated with running such a service.