XIV doesn't need a graphics overhaul considering this iteration is only 4 years old (you have to remember the original XIV or 1.0 in this instance failed hard and the game was scrapped, rebuilt from the bottom up, and re-released as ARR or 2.0). Stormblood is amazingly beautiful, they really upped the graphics quality with this release (they redid nothing but they utilize DirectX 11 now, instead of 9 like they did with ARR). I expect to see XIV go on for at least another 5-6 years considering it's still growing (last count was 8+ million subscribers) and if they keep releasing a quality game (launches with standing, they can't seem to get that shit right) and continue their patch cycle (every 3 months we get new content) this game will go on for a long while.
You also forget FFXI, its been out for 15 years and has not seen any major graphic overhauls (minor gameplay ones) and it's currently the longest running MMO to date (then again Everquest is still technically running) and it's due for a Mobile release soon (don't really know the details but it's a scaled down version of FFXI). Fuck people still play the game religiously.
WoW's game engine hasn't seen any real improvements, it's still technically the same engine but they've expanded it to do a lot more then it was originally capable of (graphically included, the graphics overhaul was because Blizzard thought it was time to leave the cartoony graphics behind (though it's still pretty cartoony).
Honestly we won't see another major iteration in consoles for another year or two and that will most likely be out of Sony more than Microsoft. MS already stated they won't be releasing a new console and wish to only improve upon the XBone going foward, maybe releasing newer versions like the S and X (considering how much money and time they put into the X they would be retarded to start developing a new console now). If anything generations are gone, we'll be stuck with similar consoles only slightly more powerful than the last. Ultimately I think the goal is to go modular, like a computer and allow us to upgrade parts going forward. While that may sound stupid it's actually not. It'll allow gamers who can't afford high-end computers to get into gaming at a cheaper cost and allow them to upgrade as they need to any parts going out of date (instead of spending $2100 like I did on my computer someone can go out, pick up whatever iteration of the XBone we're on for lets say $500, and then down the line buy a new graphics card/cpu/etc. This in the long run is much cheaper as they're still paying a smaller fee to get in whereas no matter what I'll always be spending more since my initial in was $2100). Meh, you can take that as you will but honestly I don't foresee anything more out of consoles, generation wise, other then slightly better versions coming out.