Sometimes they get detected and fixed, and sometimes they just get written off because they are small amounts.
Besides an important part of banks fixing issues like this (when they do fix them) is that someone (often the bank itself) must lose money, which they inevitably notice. In the case of an election, no one would ever know if their vote was stolen because they have no way of tracking it once they cast it. You seem to be blindly assuming that every problem will get detected and fixed which is mindbogglingly niave.
What happens when there are election irregularities detected after a winner has been declared?
2000 presidential election. Bush declared victor, but a Florida state law called for a recount as the margin was close. Recount was stopped, original election result stands. [1]
2016 brexit referendum. Leave campaign wins - and is later found to have broken campaign finance laws [2]. Original election result stands.
2016 presidential election. Trump declared victor, but evidence emerges of Russian interference [3]. Original election result stands.
There's no point in detecting irregularities after an election is over if they aren't going to be fixed - and history shows they won't be fixed. I'll stick with pencil-and-paper ballots thanks very much.
Besides an important part of banks fixing issues like this (when they do fix them) is that someone (often the bank itself) must lose money, which they inevitably notice. In the case of an election, no one would ever know if their vote was stolen because they have no way of tracking it once they cast it. You seem to be blindly assuming that every problem will get detected and fixed which is mindbogglingly niave.