I want to agree with you here, but Blizzard clearly disagree and is treating PvP like a small side-dish.
I am sure Blizzard’s decision is based on data gathered over a long period of time, also their shareholders would not allow them to not chase the bigger slice.
There is a thread in the main forum titled ‘Why don’t more WoW players PvP’. While it doesn’t represent the entire picture, it does contain some interesting points.