Difference is when this assumption is proven false in a car, it's generally more survivable than when you're on a bike or motorbike.
Remember, only three cyclists have died at this intersection over the last six years while being a popular bike route. Not every cyclist is getting eliminated here. But it doesn't take many deaths to make you go "hmm, how can we design this intersection better?"
My point is that the answer to "why don't cyclists look to see if a car is running through the yield?" is probably "most of them do". That's why there were only three deaths in six years. It's a weird question to ask because even though you could scold those three people for not driving more defensively, the signage could simply be improved (and it was).
I don't believe I ever asked, or implied, that question.
I'll just add that there's a saying amongst motorcyclists that "there's no point being right if you're dead" - sure, the car _should've_ given way, but they often don't, so you have to ride like everyone will fail to give way, to ensure you have the best chance of survival.
You can take steps to be seen - put yourself in a cars sightlines and watch carefully for signs of not slowing down. But ultimately you are moving at a speed which means if someone absolutely guns it out a junction, or changes lanes without looking, you will be hit.
Watching carefully for signs of not being seen reduces the risk, sure. Often to acceptable levels. But it's always there.
In all my decades of driving I have never seen anyone drive that way. I think I'd believe it with dashcam evidence only.
As a biker, this all applies doubly so, because one mistake like this can pretty frequently be fatal. Be paranoid or you risk death, there's no alternative.
(Note also that all-way stops are rare outside of NA; it’s far more common to have roundabouts or clear priority, but you always keep an eye out.)
Better than driving ten over and assuming everyone can see every stop sign.