Because it was used to game the CBO score for the 2017 tax bill by offsetting tax cuts with future revenue, making the bill seem more revenue neutral upon analy

Because it was used to game the CBO score for the 2017 tax bill by offsetting tax cuts with future revenue, making the bill seem more revenue neutral upon analysis. This was done under the presumption that Congress would never actually let something so insane and detrimental to American innovation and competitiveness go into effect, and would obviously roll it back before 2022. The IRS didn’t even have guidance for the change until months and months after the April filing deadline, because why would they prepare guidance for something that will so obviously be rolled back? Then Congress did not roll it back. So here we are.