Since you take "if they arrive" out of the equation, it also depends on how late, if Markiplier does an unboxing, and the total perceived value of the contents.
The later the date is pushed back, the more likely more (negative) exposure becomes. If it's late enough, I can see people cancelling their subscription and wanting their money back.
If Markiplier does an unboxing, there will be a lot of exposure.
If the perceived value is high, more (positive) exposure.