In Russia we had cameras on approximately half of polling stations (about 45 000) and the video was streamed online (the site didn't allow saving videos, but activists managed to write scripts to do it in a short time). The total expenses for this were about $41M.

I'd argue we've ended up here exactly because people are impatient and won't wait for results. If you design a system that declares e.g. the presidency two days later, you're going to run into a lot of resistance.

Use the stats to do it. Oregon does. Results come in fairly timely, and finals can take a couple weeks, depending.

It would be a way better feuilleton to get a trickle of the results during 48hrs.

More seriously, France has paper voting, yet results are published at 8:00:00pm, closing time of the last voting offices. How? Statistics. And only takes the night to confirm, when we’re on a 50,3% kind of results. And it’s already 60m voters; If it works for 60m people, it will work for 300m (especially if only 120m vote in USA).