How would you even verify past elections? You can point to millions spent on commissions and lawyers, but those can’t go back and generate data that was never contemporaneously collected.
Think of it in terms of computer security. You had a telnet server exposed to the internet for years. You have no logs, and the machine got scrapped before you ever got access to it. How would you do a security audit to determine if anyone broke into the server? You could spend millions on a commission and have the commission declare there was no security breach, but that would be for show, right?
You say people don’t look too hard for tax evasion, but people don’t look very hard for voter fraud as the voting is happening. And by its nature it’s something that you can’t reliably look for after the election has happened.
If you show up to the polling place, you need to list the name and address of a registered voter in that district. How do you know this information?
If you use a relative or acquaintance whose name and address you know they're registered at, when they show up to vote it will be noted that they have already voted. They can then put in their preliminary ballot, and presumably their signature will more closely match the fraudulent one and the real one will be counted.
There are enough basic hurdles to this that I don't see how it can even be done at scale.