The only thing stopping games from being more inclusive is the developer. Adina Shanholtz, Tobiah Zarlez, and Suz Hinton from Microsoft will tell you 9 simple things game developers could do to make their games as inclusive as possible. If more developers did these things, they could increase their potential audience tremendously. This isn't about altruism, it's just good business practice.
Adina Shanholtz [Technical Evangelist, Microsoft], Tobiah Zarlez [Technical Evangelist, Microsoft], Susan Hinton [Technical Evangelist, Microsoft]