Singular they has been around much more than the "past few years": https://www.merriam-webster.com/wordplay/singular-nonbinary-they https://www.merriam-webster.

Singular they has been around much more than the "past few years": https://www.merriam-webster.com/wordplay/singular-nonbinary-they https://www.merriam-webster.com/wordplay/singular-nonbinary-... > We will note that they has been in consistent use as a singular pronoun since the late 1300s; that the development of singular they mirrors the development of the singular you from the plural you, yet we don’t complain that singular you is ungrammatical; and that regardless of what detractors say, nearly everyone uses the singular they in casual conversation and often in formal writing.