While Intuit and their friends do lobby, the US tax code was fiendishly complex long before Intuit was even a thing.
"The income tax has made more liars out of the American people than golf has. Even when you make a tax form out on the level, you don't know when it's through, if you are a crook or a martyr." -- Will Rogers
They have no way of knowing what all your business expenses are (especially ones that don't require sending the recipient one of the various Form 1099s). They can look at what you claim as business expenses and retroactively require you to show proof of those expenses (i.e., audit you) if they seem unreasonable, but that's an entirely different thing.
Their taxes are easy, too. Just a handful of clicks through a free e-filing system. Most can also use a free in-person filing service (VITA.)
Most of the thousands of hours you hear about comes from working through legitimate complexity (complicated assets, stock splits, self-employment, etc.)
That’s not to say it wouldn’t be good to have more computing thrown at automating the rules for that complexity.
If you're an American and have 0 deductions you're seriously incompetent as an adult. The standard deduction is available to almost all taxpayers and requires no evidence, documentation, or proof of any kind: