Information on the Oregon system here from the Oregon Blue Book.
Voting

MacGrath, note that Oregon citizens voted for the method, which was then approved by the state Legislature. I am sure that it took several months at least to codify the regulations so that they would be essentially fail-safe. Whatever system is used is subject to State laws and control, and cannot be instituted overnight.

I agree with Amos (I think) that mail voting may be practical and efficient. It will take time to get agreement on any change, so I do not look for any real improvement on the current chaos for some years.

Macgrath, any vote, primary or general election, would be subject to rules set up by the State for voting. If a state has instituted machine voting, it probably would require a vote by the assembled Legislature to change the method. (most legislatures have a summer recess, there are rules for calling them together, etc.). Every state (50 of them) has its own rules, methods of registration, etc., and sets dates for the primaries or elections.
This is what set up the problem with Michigan and Florida. The political parties set rules on timing which the states (always jealous of their prerogatives) ignored and set their own dates. Which should rule? The States are legal entities that enact laws under the Constitution. The political parties do not have any authority to make laws. Can the Democratic National Committee overrule state law? I think that this will be a subject for the courts and the U. S. Congress in the next few years. It needs settling.