Given that there was significant overlap between when cannons were introduced and horses were phased out of general warfare, I have no doubt that many unfortunate horses have in fact exploded.

They get put out to pasture, selling WoW gold to each other until their server goes down.

ID age verification is a good example of something that could actually do a lot to reduce spam and ensure people are talking to real people, but it would never happen because the money is in flagging and tracking the verified people and selling access to the bots talking to them.