The reason for this is mainly emotional. The localization exclusivity for PS Vita turned the game way more unaccessible for the crushing great part of the fans, who still wait for an anime adaptation for the game (which was stated by the author to never come), and consequently, the fandom has been dying more and more ever since. Getting a more accessible translation for everyone should at least remediate that.
Also, about other games without a proper translation, I can say for myself I put effort on them, as I am part of a crew who translates the Touhou series to our native language.