I mean it's just semantics you're fussing over now. If the tip is touching the B20 on 4th down, Team A has 20 yards to go for a TD.
They throw incomplete and Team B takes over. They don't have 80 yards to go for a TD. They have 79 yards and 25 inches to go. So yes, they gained 11 inches of field position based on what the "front" tip of the ball is. Just depends on how you look at it.
No, not semantics. Real life physics. When Team B takes over on downs after an incomplete pass, will any of their players (other than the snapper) be allowed to be in or beyond the NZ when they now snap the ball? No. They couldn't do that while on defense, so their field position was, and still is, their side of the NZ. The same is true for Team A. When Team B now snaps the ball, Team A's field position is that area on their side of the same neutral zone that existed on 4th down.
There is a neutral zone between North and South Korea. If one side goes on the offensive and advances across that NZ, and expels the occupants of some area on the opposite side of the NZ, then, yes, their territory (field position) has changed. But, if the opposite side is able to resist the offensive and forces the aggressor back onto their side of the NZ, with neither side expelling anybody from the territory each occupied before the offensive began (4th down incomplete pass), then neither side gains or loses territory (field position).
On 4th down, each football team has their territory (each side of the NZ). If Team A fails to make the line to gain due to an incomplete forward pass, the field position (territory) for both teams remains as it was before the snap. Neither side gains or loses field position. That's the only way to look at it.
Like I said, during scrimmage play, each side is constantly trying to move the NZ up and down the field. The NZ is a constant of scrimmage play. It can only be moved when a subsequent dead ball (not an incomplete forward pass) is declared. For any incomplete forward pass, the NZ for the next down remains exactly where it was for the previous down, regardless of which team will next snap the ball. Neither team gains or loses any ground.
State U kicks off to State Tech. Yes, when a touchback is declared, the neutral zone is established with State U's LOS exactly at the edge of the 4-inch wide 20-yard line (or 25-yard line, as appropriate), that yard line being centered on a line 20/25 yards from the field side edge of the defending team's goal line. State Tech's LOS is some 11" nearer their goal line (the length of the ball). That would actually be 19 yards and 23" (or 24 yards and 23") from State Tech's goal line. Those two lines establish the neutral zone. State Tech has 80/75 yards and 2" to go to score a TD.
If State Tech were to throw four consecutive incomplete forward passes, that neutral zone remains exactly where it was on 4th down. State U then would have 19/24 yards, 23" to go to score a TD.
No field position changed whatsoever.
TV fabricated mechanic? Not true. I had this discussion with John Adams back in the late 70's, when I wondered about avoiding a safety by flipping the ball over after 4th down near A's goal line. That's when he educated me about the neutral zone being a constant, and that the box needs to be moved to the opposite end of the NZ after a 4th down incomplete pass.
Quite the opposite, in fact. Flipping the ball over is a mechanic by those that lack a true understanding of the rules, and/or are simply lazy. Hate me if you want. But that's the truth, and if that hurts, the hurt can stop by doing it right.