So, I dropped my phone a few weeks ago.  It was damaged beyond repair.  My new phone now wears an "impact resistance" case that is pretty hefty being mostly rubber.  The previous phone holder will not hold something this big....

Below is the new design with articulating arms.  The weight of the phone causes the bottom of the slider to move down, pulling the two arms up to hold on to the phone.  A spring pulls the slider up when the phone is removed.  Current design will hold phones up to 1/2" thick.  2-7/8" to 3-3/8" wide.