Pool is played in a two dimensional space. I agree it should stay two dimensional. Jumping potentially can also damage the table. No sense risking someone else's investment for the sake of a single shot. Similar to intentionally shooting a ball off the table in the game of one pocket. That should result in loss of game.
I don't think damaging the table is a significant issue, but the two dimensions argument is the key here. Anyone who thinks the old masters jumped more than very occasionally didn't watch them and, rest assured, a few of them didn't play a single jump shot in their entire careers.
The single most important skill found in the best players is position play. In rotation games, that has always meant making sure that obstructing balls are avoided through exceptional pattern play. Mess up the shape and the run out is over, until now ..... today, you can often recover by changing to a three dimensional game, reducing the cost of position poorly played. Add to this that defensive skills, kicking skills and billiard knowledge are all slightly devalued and it's getting harder and harder to equate the modern game with the one that the last generation of greats (meaning Sigel, Varner, Hall, Reyes, Parica, Ortmann, etc.)
I'm not a rocket scientist, but it's theoretically possible that one day, technology will allow one to shoot right through an obstructing ball without touching it, relieving one of the need to jump over it. This would again devalue position play skills, but would that serve the game well?
Shooting the cue ball into the air was, for decades, only found on blooper tapes and was the very definition of poor play --- for good reason!