1) MMORPG is about competition... a lot.
2) Competition = each player want to get more resources than others.
3) Currently solo gaming gives player more resources than in online mode - you could meet more mobs, nodes, chests & etc.
Conclusion:
People would play mainly in solo-mode if there wouldn't be any bonuses for playing MMO-mode - like extra experience or bonus loot.
SotA - MMO and solo experience
SotA - MMO and solo experience
http://youtube.com/GlazGame — streams in english // http://youtube.com/StreamGuild — streams in russian