Not that it really matters, but for those who are saying "It's been this way for 100 years", the toe-heel rule was added just this year. Here are the notes on player possession from 2023 and 2024. So the NFL thought it was ambiguous enough to at least clarify it, and that might have been ruled a catch in 2023.
2023
(1) Movement of the ball does not automatically result in loss of control.
(2) If a player who has completed the first two, but not the third requirement for possession, contacts the ground and loses control of the ball, there is no possession if the ball hits the ground before he regains control, or if he regains control out of bounds. If a player would have caught, inter
2024
- Movement of the ball does not automatically result in loss of control.
- If a player who has completed the first two, but not the third requirement for possession, contacts the ground and loses control of the ball, there is no possession if the ball hits the ground before he regains control, or if he regains control out of bounds. If a player would have caught, intercepted, or recovered a ball inbounds, but is carried out of bounds, player possession will be granted (8-1-3-Note 5).
- If any part of the foot hits out of bounds during the normal continuous motion of taking a step (heel-toe or toe-heel), then the foot is out of bounds. A player is inbounds if he drags his foot, or if there is a delay between the heel-toe or toe-heel touching the ground.
I thought it was a pretty tough play for Polk. Leaping, falling backwards, it's not easy to get that second foot in, especially when you've kicked that leg out to elevate to make the catch. I guess he could have stuck it straight out and hoped it hit first and that he didn't get a concussion slamming into the ground unprotected, but that seems like it's asking a lot of him.