Don't be silly. I am pretty certain that there is a lot more corruption going on in, say, big time college athletics than there are NCAA investigations into improper activities, much less actual punishments handed out for breaking the rules. Voting fraud is not that easy to detect, and rather difficult to study accurately. Furthermore, there really has not been all that much interest in either studying it, or trying to stop it. One major political party is determined to prevent any better understanding of the problem and appears to be in deep denial - at least officially - that voting fraud even exists. Under such circumstances the cloud around the issue is hardly surprising.
The winning party is not interested in drawing attention to voter fraud because that might raise too many questions and perhaps undermine their victory. And what do you expect the loser to say: the other side won because they cheated better than we did?
How is voting fraud not that easy to detect? If there are 800K to 5M cases of it then there should be demonstrable evidence in a pretty small sample size of votes to determine that there is widespread voter fraud. 126M votes were cast in this years election, and while obviously it won't break down completely evenly, if you just look at a 10K vote sample size then you would, on average, expect to find 63-396 cases of voter fraud. That's not unreasonable to go through at all, especially with the resources that the federal and state governments have.
Your framing of the way that Democrats and Republicans are attempting to make sure everybody who is legally allowed to vote can vote is comical.
The winning party is still drawing attention to voter fraud because the leader of that party believes in the conspiracy theory that Clinton won the popular vote because of it. Trump brought up voter fraud before the election for two reasons:
1. He sincerely believes in a lot of different conspiracy theories (that's pretty provable by just running down his timeline on Twitter...vaccines cause autism, the birther scandal, climate change is made up and a hoax by the Chinese).
2. To instill doubt in the minds of people in America, so when he lost he could easily claim voter fraud was one of the big reasons why.
Trump has no interest in actually seeing through with voter fraud other than how it fits to his definition. The man thought that being registered to vote in two states was voter fraud for god's sake.
If voter fraud were as prevalent and common as you truly think it is (which is fine), then you should be able to point out how often it occurs other than the 4 attempts that the Washington Post wrote about that were thwarted (and I believe 3/4 were done by folks who were acting due to what Trump was saying about the Democrats casting illegal votes).
It's not that hard. You can keep believing what you want without factual evidence to back it up in the real world, but when you come on here you will need tangible evidence to back it up instead of just relying on a truly fake news article from 2 years ago that is: outdated, been proven incorrect/redacted, and not relevant to this year's election. Otherwise you're going to be called on it.