It looks like Lost Ark may not come to EU and NA in 2020 after all, despite Smilegate stating last year that the game may hit EU and NA someday.
Details come via Altchar, which cites localization as the big culprit. As with anything localizing a game into multiple languages is a time consuming effort. Since language does not translate one-to-one, time and care must be taken to ensure any language and cultural idiosyncrasies make sense in translation.
Altchar also cites focus on the Japanese version as another reason for lack of an EU and NA release in 2020. Its falling popularity in native Korea might be another reason,
“…according to reports, Lost Ark is losing popularity in Korea pretty fast due to its poor endgame and monetisation model, which is described by players as ‘pay2progress’.”