You have a better chance of getting a clear picture of Bigfoot than you do of having a voter fraud incident in your jurisdiction.
Just because you don't see it. doesn't mean it's not there. It would be entirely possible that there is no enforcement... and thus no records of those events happening.
Just like "illegal" border crossings. Current numbers state "Nationwide Encounters" is the number that CBP publishes. That's not the number of border crossings. That's the number of people that law enforcement has encountered and handled. This clearly ignores those who weren't "encountered" but still made it over. Part of that "encountered" number would be things like, "how many border guards do we have to actually 'encounter' these people?" If you fired 100% of the border guard force. Well your "Nationwide Encounters" stats would also drop to near 0. That doesn't mean that there are no longer any border crossings.
Poll workers collecting votes on voting day have no way to validate if your voter registration is not valid. It's either you're on the list or not. And in a lot of jurisdictions, simply getting a driver's license is enough to get your name on that list, even if you aren't allowed to vote otherwise.
Let's make some safe presumptions. There are at least some non-zero amount of people who vote illegally (ignore if they're "illegal immigrants" or not, just in general). How is discarding their votes and pursuing those felony charges enforced? Is that effective? If the answer is "poll workers", how are they supposed to know who on their registers are not supposed to be there in states that do auto-registration? There is discussion to have here without even bringing up a singular specific source of fraud like this article does.