This play could have easily been ruled incomplete. But I have no problem with it being called complete either. It is the exact example of being completely on the boarder.
This play should not have been ruled a catch because Cruz only got one foot down. It was erroneously ruled a catch -- here's the important part -- because they thought he'd completed
the catch process (control + two feet down + football move). In this case the football move was his reach for the goal line. Because he'd completed the catch process, he didn't have to hold onto the ball when he hit the ground. They thought he was a runner.
The following has been true for decades:
"to complete the catch process" = "to become a runner"
Over time, the catch process underwent several changes, but beginning in 2011 a player completed the catch process (became a runner) if he...
A) had control of the ball,
B) got two feet down, and
C) maintained control long enough to perform any act common to the game
A player did
not have to be upright in order to complete the catch process and become a runner. Item 1 ("going to the ground") addressed players who don't complete the three-part process before they hit the ground. It said that even if the player went to the ground, he could complete the process if he maintained possession after contacting the ground. This is also known as "surviving the ground."
In 2015, when they added "a player is considered to be going to the ground if he does not remain upright long enough to demonstrate that he is clearly a runner," it effectively created a new standard for completing the catch process if the player was not upright. It also meant that there were now two definitions of "becoming a runner" in the rule book at the same time. Both definitions agreed that a runner is a player in possession of a live ball. But they disagreed over how the player obtained this possession. According to the older definition, he completed the catch process. According to the newer one, he completed the catch process
while upright. "Upright long enough" wasn't added to the the three-part catch process, but was instead put into Item 1 ("going to the ground").
Also in 2015, as a companion piece to that aforementioned change, they removed "advancing with the ball" from the list of football moves in part C of the catch process, leaving "the ability to ward off a defender" as the only football move. These two changes made the older standard meaningless. How? Because you can make football moves and be able to ward off defenders while not being upright long enough, but you
can't be upright long enough without also being able to ward off defenders and make football moves.
That's why there was virtually no practical effect when the catch committee spelled out several football moves and they were added to part C in 2016. (Yes, they tried to fix the catch rule after just one year of "upright long enough.") But part C had already been emasculated, so no matter how they changed it, it could only affect plays that involved a player losing control
while still upright. After 2015, it could only
ever do that. The real problem lay in the types of catches that involved going to the ground. If there was to be a practical change, it had to happen to Item 1 ("going to the ground") where they had put in the requirement of remaining upright long enough.
This past week, they said that they're eliminating Item 1 completely, which along with it eliminates the requirement to be upright long enough.
How that requirement got in there in the first place is a whole other story, but it started in Green Bay.