Just like the multiple generations who have flown the Buf. B-52 for those who do not know it as the Buf.
The KC-46 was chosen for many factors:
It met the KC-135 mission and required no additional infrastructure improvements. 330 would have had millions spent on this.
The KC-46 was more...
Lets address a couple of items.
Boeing has already delivered 767 tankers to Italy and Japan.
Making a blanket statement that Airbus is better, since they have delivered tankers is bad...