It just isn't designed to makes things easier. That is a happenstance (if you don't do withholding you submit quarterly estimate payments which while annoying isn't much harder than tax season)
It is designed to minimize the IRSs job by focusing on businesses rather than individuals for the bulk of taxes.
Which... I can see an argument for. Especially when coupled with regular payments vs end-of-year.
It's silly for everyone to individually have to think about "How do I get these dollars to the IRS?" all during the year.