I have the same thing and blame it on poor pollination. It was cold and rainy through much of our cherry bloom and very little bee activity. Al

Same here, terrible year for cherry pollination. i still have a bumper crop, though, mostly on Royal Lee, Royal rainier, lapins and merton late.

Shake the tree, most of the un-pollinated cherries should drop to the ground.

Same problem here... How frustrating, this was supposed to be the first good crop.
Can there be any other reason for the fruit shriveling like that?

I doubt pollination is the issue if the cherries actually sized up to half full-size. I have seen this too and my belief, for what it's worth, is that the tree is simply dropping fruit to reduce its load to an acceptable level. That level may be zero on a young tree. Cherries take quite some time to bear much fruit.

shriveled or soft pit = insufficient pollination.