As far as I know Zotac GTX 560ti had two types of aftermarket coolers. Either a single fan 3 heatpipe version with a copper base plate or a shorter single fan 2 heatpipe version with a copper base plate. As you can see that type of configuration is not going to do wonders in terms of cooling. They were more budget oriented cards offered at a lower price.
Modern aftermarkets now typically default to 2 fans with higher end ones using considerably larger total fan area and heatsink mass.
Zotac by the way is actually a subsidary of the same company that Sapphire is who is considered AMDs best partner in terms of custom board designs.
I still think the largest issue, which is shares with Sapphire, is that the warranty on paper isn't tranferable which hurts resale.
EVGA is selling the ACX 2.0+ cooler for the Titan X, but has said they have no plans to offer the two together out of the box. I ordered one for my Superclocked Titan X and I'll have it next Tuesday. It should be able to fit any Titan X since the PCB has to follow NVIDIA reference. It even comes with a backplate and thermal pads.Zotac uses such shitty non-reference coolers on their cards. Just because it looks fancy doesn't mean jack. I got burned (or I should say, my GTX 560 Ti got burned) by a crappy cooler that couldn't keep the card from hitting 95C and throttling at stock speeds. I would never buy another video card from them again, certainly not on the high end.
FWIW I got the EVGA Titan X SC and the reference cooler works OK for mild overclocking (not great, it's definitely temperature limited), but I would rather see a custom aftermarket cooler than anything released by Zotac
Most likely nVidia wasn't letting them offer it on the card for retail. They wouldn't have much say in EVGA making aftermarket gpu cooling though as long as it wasn't offered on the card. With this news from Zotac maybe nVidia is loosening up their restrictions and EVGA might be able to do it. Pretty sure from watching EVGA's product line that they will want to stick as many of their own coolers on anything they can.