Pretty much what desi said. These titles are cheap and quick to translate, and they're guaranteed to bring profit.
Additionally, I'd like to note that it was "that" dreadful AX panel that caused so much not entirely warranted discontent about MG. People expected at least some story-driven titles to be announced, but there were none. It was a really bad move for MG, but in all honesty, it's not like the ratio of cheap nukige to story-driven titles changed that much. MangaGamer always has at least 2 and as much as 4-5 story-driven VNs in the works pretty much against business sense, as those