I'm going to be good, and eat my plate of crow on this one...
Last night, when I made my post, I was feeling very hopeless in regard to ever getting the Ixion mount, and I spoke before doing recent patch research, which meant that I failed to realize that SE had raised the reward rate on horns (from 2 horns to 6 upon achieving Gold status). Ixion spawned 3 times today, and each time there were ample players present to complete the FATE, and everyone who was present for at least 2 spawns (myself included) was able to obtain the mount. Therefore, I redact what I said last night in regard to the impossibility of most players obtaining Ixion, and apologize for jumping the gun before I had updated my knowledge on the matter.
Irony is a painful mistress. -.-