My running theory is that, because the majority of PC work is being done by SEGA Europe, and Atlus has shaky relations at best with European markets, there's no interest or even attempts over there to bring games over. I remember when Atlus was first bought by SEGA, everyone's hope was that it'd mean more Atlus games in Europe. But nope, SEGA Europe has no connection whatsoever.
Of course, there's also the issues of SEGA being hands-off with Atlus and all of SEGA's branches working independently. I'm sure there is some interest in bringing the games over to PC, but probably not at Atlus Japan, and getting that conversation going is likely difficult.