The answer of course is that the IRS doesn’t know how much you owe, and it isn’t feasible for them for figure out exact numbers for everyone with the tax code as complicated as it is. So, they audit a fraction of Americans every year to keep everyone honest. It’s a bad system that taxes are so complicated but it’s not a conspiracy.
It absolutely is a conspiracy though:
Except the federal government literally this year started instituting a free, public filling service to get around TurboTax. And they fought it tooth and nail.
There is a conspiracy, but it’s not a federal government conspiracy. It’s just a bad system that certain companies conspired to take advantage of.