It’s not just the population density, it’s how that density is laid out across the geography.
In Australia, which has a population of around 285 million fewer people than the US btw, 80% of your population lives within the coastal zone. In the US, it breaks down differently, about half live in large cities with the other half rambled out across the countryside.
Voting is considered a civic duty here too. Our lower turnout is due to the nature of having 2 main political parties rather than 3. If you only had 2 parties and vote weight was by territory rather than one national vote, you’d have lower turnout too. I agree that the disconnect between the Constitution (which was not written with only 2 permanent political parties in mind) and Republicans vs. Democrats has become a quagmire we can’t seem to work ourselves out of, but it’s disingenuous to suggest that voters on the whole are flippant about the civic duty of voting. We’re not.
The problem is not the machines. They’re safe, they work, and they’re efficient. They must be tested and certified before being put into service. They can be audited after an election. Most states require an audit to spot check the vote. They are also not a requirement.
The problem is the lack of good will between parties and bad faith to small d democracy by one of those parties. The Republicans have admitted before the Supreme Court that the only way they can win is if less people vote. The machines don’t cause the lines, attempts to make it harder for people in Democratic strongholds to vote is the reason for the lines. If you’re not in one of those strongholds, it’s cake walk easy to vote.
The inevitable conclusion being that going back to paper and pencil only will not make anything easier or more secure or end the political turmoil. Bad faith and ill will means that Republicans would just come up with some cockamamie theory about how ballots filled out with golf pencils magically change votes from Trump to Biden, disenfranchising Trump supporters. Or that Trump voters are being silenced because thermal paper print fades in direct sunlight. Trump supporters will swallow that without ever thinking about it. Cue up the outrage and uproar.
Did you wonder why the furore was only over the Presidential vote but there was no question of all the down ballot votes made on the same ballot? Ever wonder why in these battleground states you can have lawful and correct election results of Republican governors but the President was defrauded off the same piece of paper and the number of paper ballots equals the number of votes and the manual counts done 2 and 3 and 4 times came to the same results as the machine scanners?