What I find interesting is that the biggest proponents of dynamic language -- the idea that usage evolves over time, such as "they" becoming more common as a singular pronoun -- also tend to treat a word like "guys" as non-gender-inclusive, even though it is extremely common for "guys" to be used in a gender-neutral way when used in the second person. "You guys" and "Hey guys" are examples of this, and what a lot of people ignore is that women have had a large part in moving these terms in a gender-neutral direction by using these phrase to address other women.