When it comes to the length of the track you need to remember that drag racing in the west side of this country was started to try and stop kids from street racing, which was stoplight to stoplight or when ever the other guy let off when he was behind
Riverside Raceway tried 1/2 mile drags for a while, it didn't last long due to a lot of the racers blowing their motors up between the 1/4 and 1/2 mile finish line
As far as NHRA making decisions on the lengths of the tracks, insurance costs have to come into play, same thing on most track operators also
My current S/P car runs high fives at 115 MPH in the 1/8 mile and 9.00s at 147.+ MPH in the 1/4 mile so it spends a little over 45 % of it time in the 1/4 mile running the last 1/8 mile
It gains right at 30 MPH in the last 1/8 mile in less than 4 seconds but goes from a dead stop to 115 MPH in 5.85 seconds in the 1/8 mile Which is more thrilling