Um, you think a car should stop on a 5 lane roadway in case the guy in the Jeep, pulling out of a driveway, doesn't? Let's not get carried away here. I think I should have slowed enough to put his trajectory in front of me, that's all that was required. No car anywhere would (or should) have stopped on that road (preemptively). A car in my situation "should" have slowed down as I would have, but in practice there may be 1 in a 100 drivers who actually would do such a thing preemptively.

I think in driving defensively there is a point at which you must assume you've been seen, and I think that cars can reasonably make this assumption more liberally than bikes.

If I'm on a collision course with cross traffic at point A, I slow down enough that our trajectories no longer overlap, adding a margin. If the crossing driver slows down at point B, we still aren't on a collision course because of my margin, also I continue to adjust. The moment the driver completely stops at point C is very shortly before I proceed beyond my stopping distance. Now there is a point of no return and I have to judge the driver's behavior. I shouldn't have to stop in this scenario unless something awkward happens.

If the cross traffic is already stopped and I'm approaching, I should slow down and open a palm if I'm coming in too hot and their intentions are unclear. I'll continue to slow down if I still can't get clarity, but at some point if the car remains stationary I'll move out in front of it at low speed (possibly shouting "hey"). I'm not going to stop unless something is wrong (the car moves, the driver is looking the other way as if he's timing oncoming traffic, etc).