Sorry if this has been mentioned?
As the MPH goal goes up, or the engine's RPM power band shrinks (and especially if both), the value of a relatively small RPM % drop on the shift into high gear increases.
Yes, even though there are competitive cars with Powerglide and/or Gear Vendors (both of which have a geologic fault between penultimate and final gears) many would be faster if the gap were closed up, and (where necessity dictates) the gap transferred to a lower gear pair where weight (not air) is the primary resistance.