I'm so very sad that "they" was chosen by whomever, instead of our perfectly useful gender-neutral English pronoun "one".  As a teacher, I have taught a couple of "theys" and as an English teacher, I find the singularization of the following verb sounds AWFUL to me.   I also believe that the use of "one" eventually could have become a default pronoun (sort of like Ms. is the default honorific when you don't know whether a woman prefers to be called Ms., Miss or Mrs.) which I feel would go some way to actually loosening our grip on gendering everything.  To my mind, a great opportunity has been missed.