It's not just the accountancies. Planet Money did a bit about how right leaning organizations like Grover Norquist's "Americans for Tax Reform" opposed pre-file

It's not just the accountancies. Planet Money did a bit about how right leaning organizations like Grover Norquist's "Americans for Tax Reform" opposed pre-filed income tax returns because they believed that making tax compliance less painful would lead people to be less opposed to taxes generally (I can't say they are totally wrong there). Special interest groups (including some thay aren't so special, like anyone with childcare costs) on both sides love "their" special tax deductions. The accounting firms aren't campaigning for simplification, but they are joined by a legion of others opposing it in various ways as well.