I don't think the majority of players made a decision

I don't think the majority of WOW TBC Classic Gold players made a decision on their FACTION due to racials in vanilla. It wasn't my experience at all was having back then. In fact, our Rank 1 friend I had a few games with decided to go with Tauren because he was convinced that they were cool.

No one said entirely, but it's not an accident the factions started out and then ended up as they were...easily explained in the previous paragraph. I'm not going pretend that it's just a matter of people wanting to play with their friends. That's absurd.

There was one dominating EU Horde guild, but in the list of boss targets killed first in vanilla, it's something like... 7 horde vs 40 alliance world first kills. It wasn't even close for me as someone who was part of a world-first pushing guild. While great players can still be successful in cheap Burning Crusade Classic Gold vanilla horde, it was much simpler to become an alliance player prior to.