Seeing as how we have to use both a forename and surname, the likelihood that someone has the exact name you want is pretty slim (outide of names taken directly from say another game or sn anime or something).

Say I take a break from the game, long enough for all my characters to become "inactive". When i finally come back all of my characters would be gone and i'd have to start from square one. I'd quit the game entirely. It wouldnt be in SE's best interest to delete players' characters. They did it in FFXI for the first few years (for apace concerns iirc) but stopped.