It was nowhere near as bad as the giant gym chains or any other number of businesses.
I can think of a lot of membership and subscription services that have been far harder to cancel that I wish the FTC would do something about. A few extra clicks to cancel Prime is nothing in comparison to the gauntlet required to cancel some gym memberships. I remember a story where someone forgot to cancel their gym membership before moving across the country but the gym's policy required that you cancel in-person at the gym. They had to pay the monthly fee until their next trip back home, then lose an hour traveling to the gym to fill out the cancellation paperwork.
They did that. The FTC had a simple click-to-cancel rule that was supposed to start enforcement this year. It was struck down on procedural grounds during appeal in July.