Your pH example actually proves the opposite. pH 7 is not neutral because it happens to sit halfway between 0 and 14.

pH is not inherently limited to that range at all. Sufficiently concentrated solutions can have pH values below 0 or above 14. A solution is called neutral when the activities of hydrogen ions and hydroxide ions are equal, which happens to correspond to about pH 7 at 25°C. Change the temperature and neutral pH changes too. So if you arbitrarily changed the scale to 10–30, that wouldn’t magically make 20 “neutral.” Neutrality comes from the definition and the underlying conditions, not from being the midpoint between two numbers.