How on Earth are we able to have a global digital financial system that is able to keep track of trillions in transactions per year but running a seasonal election with < 100 million participants through a digital system seems too hard?
Listing a few: Market incentives, general competency of the organizations running the systems, government procurement using the same set of bigcos who only care about getting the contract not about delivering quality after. Not that I have an opinion on paper ballots but I understand the concern for such a sensitive system.
If electronics is involved in the act of voting, the voter has no assurance that the ballot remains secret (even if you're a software engineer!). With paper/envelope/box, by contrast, the voter can see and understand the full process.
This is a solved problem in India [0] - and the system is brilliant in its simplicity[1]: Fixed function non-reprogrammable battery operated electronic units, no connectivity, randomization of voting units and a paper trail for verification.
Because of the incentives of the US voting system. Voting is not mandatory so parties are incentivised to mess with voting access to make it easier for their demographics to vote but not others. There's also a general distain for letting 'the wrong people' vote in America.
Those handling the financial system have an interest in it running right whilst those handling the election system have an interest in tampering with the results.
Even if you ignore all technical problems - the problem with electronic voting is that it provides a breeding ground for conspiracy theories. Even if an election is run perfectly legitimately, bad actors can make credible-sounding claims around hackers editing votes, or voting machines being rigged.
