3/4 of the cue is the shaft.
No standards of any kind in snooker either, different joints, diameters, ways of installing the ferrule etc..
As mentioned it's more manual labour involved and the tolerances arent as tight as you think, I've done quite a bit of snooker cue repair lately and you quickly notice that the cue is hand planed when you change the ferrule, none of the shaft I've worked on have been truly round, so gettig a ferrule flush is not like on a pool shaft.
Why they use heavy brass hardware and a 3/4 design, I'm not really sure about, I think the answer in large part is: tradition.
But things seems to be happening in snooker, phenolic and Ti ferrules, Kamui, G2 and others now make 10 and 11mm tips, lots of high-end chalks and I've even seen a snooker pro using a glove!