I will say this in regards to the solo players forcing them out of their comfort zone.


I was once one of these people whom had terrible social anxiety for an online MMO thanks to the preconceptions about online toxicity with group content in other games such as WoW. So when I started FFXIV, I didnt know what to truly expect, the only thing I knew was that for me whom was just only interested in going through the story I knew that I'd be having to eventually go through dungeons or other content to progress which requires interaction with other players. And due to how the game made going through dungeons, knowing your class and combat very simple and casual I slowly broke out of that mold and wanted to continue interacting with other players even more.

So I think the solution here is that you'd want the game to make you WANT to interact with players and have fun. Instead of trying to go for absolutes, continue to design the game to slowly ease in new players to play with other people.