As others have said:
* These days, phone numbers are something you enter once, and forget about. Computers and phones now remember them for you.
* Phone number pads are, arguably, "more obsolete" than calculator/computer numeric pads, and so the world should move to the "789" keypad style. (Here, "more obsolete" is relative, as we'll still have telephone keypads for years to come.)
* Even if you're right, the majority of people don't really care. And, if either keypad were to change, the public outcry and complaints would likely be of biblical proportions. Bottom line: nothing's going to change.
If it really bothers you, pop off the numeric keypad keys on a PC keyboard, and remap the scan codes. With MS Windows (from XP onwards, IIRC), it's pretty easy to remap scancodes deep down in the keyboard driver, using the registry. I do this to swap the caps and ctrl keys.