I really wonder about this estimate. I worked on a couple hundred returns this year, and only one of was even close to this time. It had several W-2s, two Sched Cs, a home sale and some brokerage docs. The couple was completely disorganized and had to visit us three times because they were missing info about their home's basis, their business expenses, and one of the 1099s. Possibly if you add up all the time they both spent looking for info at home and then working with us on their return you might hit 11 hrs, but this is definitely not typical.
The average return we do takes about 90 minutes including filling out our intake sheet and having a second person do a quality review. A return for a single person with just a job or pension and SS is under an hour for the entire process. I keep reading about how the typical American has very little savings and can't afford to buy a house, so the idea that it takes this person 11 hours to do their taxes just doesn't make sense to me.
That said, I do agree that the IRS should be able to do the income part of most returns automatically. They can't do returns with rental, farm, fishing or cash business income, but the majority of taxpayers don't have any of that. Making it possible for the IRS to do the entire return means we have to rewrite the tax code to eliminate most credits and deductions, which would make us more like all the countries that do have automatic tax levies.