There's been a solo rpg movement around for a long time. And solitaire is literally one of the og single player board games - it's literally in the name (translates to lone or loner)! And personally, I consider all fiction authors and screenwriters to be solo rpg gamers, they just don't have to abide by any specific rules other than their own. There's room for both social and solo pursuits in life and it's not necessarily depressing to engage in the solo if the person is enjoying themselves.