More memory can be useful... Outside the game. For example, in the days of DOS when you needed special drivers to be able to use more than 640K ram, we used the extra ram between 640k-1MB to stuff drivers into, and anything above that as a Ramdisk. We'd actually copy the game to the ramdisk where it ran faster because of ram access times and not having to bother with rotational delay and seek time.
Technically this concept should still work, perhaps even better since we now have direct access to the upper ram... Judging from the specifications I've seen for SSDs a ramdisk could easily outperform one.
That part isn't true any more. I constantly have out of memory issues with only 8GB. 16GB is the bare minimum for a gaming rig now, and 32GB would give you nice headroom for the future. Especially since we are moving into 4k, we should see a leap in textures and models, and thus RAM required. ( There's a reason Nvidia just announced a video card with 12GB of RAM on it. ) They're also starting on 8k monitors and TVs, which would necessitate another leap in the textures and models so that their lack of detail does not show with the higher res.
Also wanted to clarify this a bit. True in the case of Minecraft, but not gaming in general. There is the speed ( as well as latencies ) of the RAM which makes a big difference, as well as simply the amount in most games. Typically you can use more memory than you have RAM thanks to the pagefile. However, it's notoriously slow, so having more RAM will give you a significant performance impact. Naturally as a gamer, I would personally say that if you are getting into the pagefile, then you NEED more RAM, but others are content with it just working.
Again though, it should be noted that in the context of minecraft, everything you said is pretty valid due to the limitations of Java However, every version this is getting better. Their focus for awhile now has been improved memory handling and garbage collection. Java 8 already saw pretty big leaps here, and I believe they said 9 is supposed to be centered around that as well.
First off sorry for doing a bit of spam between the tech stuff and my noobiness with editing quotes into a post, but as far as I can tell 8 gigs is fine for now, unless you have like 10 chrome tabs while you are playing or have 7 gigs allocated to something, as the "Next gen" AAA titles are still running fine with 6 gigs allocated. 4k is not going to be a thing really until later forms of the 900 series cards or a strong maybe for the 300 Amd series, as 4gigs is not much for 4k gaming, hence the 8gig 290x and the future 12gig titan(although I do not know if this will be a single gpu card myself, as if it is a double gpu card it will really only have 6 gigs usable) and if anything 1440p is the next jump in my mind. System RAM does not have as much a affect on games period, with Rhn said it just needs to be enough and no more, and the same goes for speed and latencies, which make almost no difference in game(rendering and other things it is different story, but for gaming you can just check the Linustechtips vidoe on fast ram.) Other than that though you are correct, and I don't mean to just be the guy that corrects people with walls of text, just want to inform and suck at communicating quickly.
While chrome does eat up ram like no ones business (heard once it was something about how chrome runs all the tabs separately so if one crashes it doesn't take it all down, don't know if that is true or not) I have yet to see it use more than a gig myself even with 1080p 60fps, although this could just be me. I still do not see 4k (or as you pointed out UHD) gaming being a big thing until graphics gets a kick-start toward it since even with the great monitors that have come out it is still pretty hard to run without high-end graphics cards, possibly in SLI/Crossfire. Happy to hear the Titan X is single with 12 gigs, as that means I may (hopefully) change my mind soon, I really do hope 4k becomes a standard thing soon. as for ram, ahhh, sorry, that's my fault for misunderstanding you there as that is completely correct on ram quality
How long of youtube videos do you watch? I think it might be from buffering an entire video. 3 minute videos, even at 1080x60 would be quite small, but a 1.5 hour video would be quite large.
4k certainly has some time to go before it becomes the standard, but this next year should see a fair bit of improvement. Fingers crossed, because it's about time. 1080p just doesn't cut it. AA should not need to be a thing.