A problem unsolved

I see via a Jason Soon tweet that the matter of "shy bladder" in men's public toilets is still the subject of articles, this one in Vox.  

I first posted about this topic in 2007, and made the very reasonable observation that, with modern public toilet design for the last few decades going nearly always with the individual ceramic urinal, it is dead easy to give each user a bit of privacy by installing simple, solid dividing screens to the wall between each one.  They don't have to be floor to head high; and I would assume that you'd really have to have a very serious aiming problem to ever miss the urinal so far that you could dirty one.   On the occasion I have been to a toilet incorporating such a design, I liked the additional bit of privacy, and I'm sure I would not be alone.

But yet, I have noticed over the intervening years that, even with new toilets in renovated shopping centres, this is pretty rarely an option taken up.

Why? 

As the Vox article notes, and as any male knows, there is a lot of use of the toilet stalls by men who only want to urinate, causing dirtier toilets because of poor aim, etc.  

This is a well known and understood issue, so why is one obvious, useful and cheap design addition to public toilets routinely ignored?

Clearly, this is some bizarre failure of the free market, and it calls for government regulation!   (An approach Jason Soon would surely endorse - ahahahaha.)