I think there are multiple causes for failing to stop at crosswalks - many of them listed here, but I have a few to add.
Note, none of this excuses what happened to BH.
First, in many states, unless a crosswalk is marked, pedestrians do not have the right of way. I believe California is the biggest, closest one. When you come here from there and get a driver's license - there's nothing that you get that clearly states the differences between laws there and here. The 90 page driver's manual full of typos and incorrect information (they should simply skip their first aid section and their airbag information among others), doesn't do it's job. The "stop for me, it's the law" signs only at marked crosswalks, don't help, only further mislead.
Second, according to an couple of city employees I talked with about this issue (different location) unless you are standing in the crosswalk area on the street, you do not have the right of way. Waiting on the curb at a corner or crosswalk, doesn't count. There are good reasons for this, but on streets like Phinney, that takes a leap of faith.
Interestingly, more signalized crosswalks make the problem worse, as drivers rush through unmarked or unsignaled crosswalks in the area at an even higher rate than before.
I also get really frustrated with pedestrians I see weekly or more, who wait on the corner 3 feet back while they have a block of free space to cross, then step out in front of my car when I'm 40 feet away.
No easy solutions.