BWV is also a few years older, which means for owners who buy for the short term, they are farther down the cycle. i.e. the typical short term owner might buy when the youngest is four and Disney is a great family vacation. Ten years later the youngest is fourteen, the oldest is in college, and they just don't go to Disney like they used to (this may not be the typical pattern here, where most people on this board are adult Disneyphiles). So they sell (and maybe rebuy a timeshare in Cancun or something).
I disagree that its easier to get into BWV than BCV, because it isn't that simple. The appeal of BWV for a lot of folks is the "view rooms" Either the BW View or the low points Standard Views. Those are (IMO) more difficult to get into than BCV. But if you just want any old room in the vacinity after the 7 month window opens, BW Preferred are likely to be available last.