Not a history expert. But I believe dota (defense of the ancients) was (one of?) the first games to create this genre of tower defense in 5v5 with the focus on heroes and skills instead of RTS marco. When others came along, they were initially referred to as “dota-like”, which obviously was not acceptable marketing for RIOT. Hence they coined the term MOBA, which come to think of it doesnt really mean anything? (Multi player online battle arena?)