True! There are creators that possibly got featured thanks to their popularity on the internet, or had a featured comic before, and some thanks to their friends who are also featured authors. There are also comics from Naver that also got featured on LW.
But there's a previous featured author that I also made the same question as you, they already completed their comic, and made a new one this year, it got featured on the recommended titles for a couple weeks and it was at the first on the list. I wonder if the author tried to sell for LW before launching it to discovery and they tried to see how much popularity it would get before thinking about it hmm
Maybe I'm just speculating too much, but the same thing happened to The Devil is a Handsome Man when it got featured on the recommended titles, it stayed there at the first on the list for a while and suddenly the author said something about reviewing the previous episodes to make it good, then the announcement of becoming featured came out