The gist is that Portland drivers couldn't stop hitting crucial safety infrastructure (proving its necessity) so PBOT gave up on it.
As one of the commenters pointed out: Since a pedestrian/bike fatality costs PBOT nothing and replacing a concrete planter a car has demolished costs them more than nothing, to balance the budget they're going to go with more pedestrian deaths.
Imagine being so bad at driving that you can't avoid hitting a bright yellow concrete cylinder sitting in the middle of the road when you're doing 25kph.
Not every intersection should or needs to be replaced by a roundabout, especially on local lane intersections where speeds are already supposed to be low. They take up more space, are more expensive to maintain (than a stop sign-controlled or uncontrolled intersection), and are also less convenient for bikers as well as cars.
Alternative: recycle old, large pipeline and pour concrete between two different diameters of it. Should hold up better to being struck by idiots in vehicles
We really need a higher standard for possessing a drivers licenses if people can't be trusted not to hit large, stationary objects on the regular... All of the forced incentive to drive in this country has made it into something people take for granted. It's easy to forget you're operating heavy machinery capable of high speeds.
I'm not sure why the people who put these in didn't expect there to be lots of collisions. There's a reason why obstacles are generally not placed in the middle of the road...
They're usually placed in such a way to prevent people turning far too sharply risking hitting someone in the oncoming lane, usually near the crosswalk. If people are having trouble with this they're having trouble with pedestrians too
I think I understand what you're getting at but your terminology is backwards - what you're describing is a wide turn. The obstacle is actually making people turn very sharply. Maybe my sense of scale is off, but the intersection in the picture looks it might even force some larger vehicles to make a three-point-turn.