This is a dumb question, no doubt triggered by Fox's petty and partisan decision not to use that term.

Let's humor it for a minute. Why is it dumb?

http://Dictionary.com  calls 'president-elect' "[a]n Americanism dating back to 1815–25". https://twitter.com/jimzarroli/status/1324728869082046465

Google's Ngram Viewer bears this out.

Losers in presidential elections started formally conceding around the turn of the 20th century. William Jennings Bryan's telegram to McKinley in 1896 started that trend. https://www.npr.org/2020/11/02/929085584/how-to-lose-an-election-a-brief-history-of-the-presidential-concession-speech

Since 'president-elect' was in use well before that, it wasn't tied to the act of conceding an election.

The term, as the above graph shows, began being used more commonly around the time concessions became en vogue. But it predates the tradition of concessions.