The NFL has been kneeling to ice games for as long as I have been watching football, some 40 years.
For some teams like the Giants back in the late 70's it is hard to do. Snaps can still get fumbled hence the 2 guys behind the QB now. An Ice play still needs to be executed.
I have no problem with a couple kneels at the end of the game to run out clock especially after a team picks up a 1st down to ensure another set of downs that will run out the clock.
I think it goes back to player safety who wants to see an RB or QB get a knee blown out running 3 plays to end a game they are leading and controlling?
I think from a player safety point they will have to make a rule change to prevent this type of play. If you watch it the TB players are just looking to go down fighting. They were no where near Manning nor were they trying to get the ball plus they had guys going out of their way to jump into the pile well after the play ended.
Officals in the mean time can blow a quick whistle once the QB kneels then throw flags for PF's for jumping into the pile. Once the league starts fining guys and it is ineffective it will die.
I think Schaino(?) will be a pretty good HC in the league, no need to ruin his rep by pulling stupid **** the rest of the league doesn't like or want to see.