Nice post about HTN which is a chronic disease and might be resulted in various complications as you have mentioned it not treated effectively. But during clinical practice, we do not follow this range always unless other organs are involved.

Normal blood pressure is usually below 120/80 mmHg.
Blood pressure between 120-129/80 is considered an elevated blood pressure.
Blood pressure between 130/80 or above is definitely High.

A persistent rise in blood pressure above 140/90 is considered as HTN when treatment is warranted. If kidney or heart is failed then we need to control in much lower level.