I don’t know how recent it is, but it’s definitely a change since the 60’s. (I’m sure it’s quite later than that.)
At least one league somewhere will stop the clock if the team with the ball loses yardage on a play. I seriously doubt however that the NFL Competition Committee will ever implement a rule like that.
My Opinion is that any Knee with over 40 sec left in the game should be a 10 yard penalty against the Offense, Unsportsman like conduct.
The Defense has every right to go after the ball, as long as they are within one score to tie or win.
Under 40 seconds and more than 7 to tie or win…the defense needs to concede defeat. Otherwise get fined for Unsportsman like conduct. Because that is officially the last play that needs to be made. No need for extra contact.
Going back to Tampa Bay…It was under 30 sec…and they were within one score, they had every right to try for the ball under my rules.
Be an interesting idea…but that’s all it will ever be.
On second thought…maybe, Intentional Gounding would be more specific, 10 yards plus Loss of down for Kneeling before 40 sec mark.
Clock management is part of the game and in its own way adds to the tension (teams see it coming before they get there).
Hell, even chess has clock management as a component.
Thinking on it more I would submit that any game which has a time limit makes the clock part of the game and people will play the clock as well as the game.
Yea I know…
My idea was just …lets play the game till the last play…if you want to kneel beforehand there’s a penalty to do so, plus a loss of down.
So, you can only do it 2 times effectively…from 1:20 sec left.
(hmm why does 60 sec plus 60 sec = 2 min, but 40 sec + 40 sec = 80 sec = 1:20 same as 60 sec + 60 sec = 120 seconds which is not = 2 min)
Anyway…I think 4 kneel downs is a cheesy 2.66 min Offense. 
I think 4 kneel-downs is equivalent to a reeeeaaaaallllly slow turnover.
And on the other side of the question, “delay of game” can be assessed for more than just the play clock running down.
The non-time-related infractions include mostly two kinds of activity. One way is slowing down the game after the play is over. For example, spiking it or tossing it away, taking too long to get off the ball (or the player who has the ball).
The other kind is preventing a play from properly starting. The defense trying to fake the start of the play (draw the offense off) is one. The rarely seen one is not letting the refs get into position before snapping the ball, since that’s actually a case of playing too fast.
This is why the last minute of a basketball game is often the Most Boring 15 Minutes in Sport. Sometimes a game is improved by letting it end cleanly.