What are the key factors that make an RPG a recognizable brand name?

I hope this is the right place to be asking such a question because it's just that I was sitting down to enjoy a quick round of Disgaea 3 when I started to realize how games like the Disgaea games aren't quite big sellers.

Like when I look back at the PS Vita of Persona 4, the best version of the game was basically locked on that platform until just a couple of years as the modern version of the game made me interested in seeing what makes ATLUS's games so easy to recognize since their games are very successful in both Japan and the USA.

My point is basically that I noticed some JRPGs such as the aforementioned Disgaea 3 as well as Disgaea D2 look like they were abandoned because if I remember right, NIS's RPGS aren't huge sellers, so I wanted to better understand what again just what were the key factors in making an RPG based IP more recognizable so that the games could sell better or something like that>