You said it your self; "to keep". The resolution lowering helps prevent the loss of a few frames, as I already said more than once. It's keeping a 60fps game at stable(r) 60fps. It's not making a 30fps game 60fps. Tomb Raider DE on XB1 did it too, though funnily enough to prevent it from dropping below 30. Dunno why you're proving my own point for me.

Crysis 3 900p vs 1080p on the same graphics card.  900p runs on average 10+fps higher.  So 720p "may" run 20+fps higher.  10+ isn't just "a few frames."

https://www.youtube.com/watch?v=ZQ4k5T6zmJw

I'll assume you have not read most of the posts in this thread, but if in the off chance that you have, its a pity this is all you got from the explanations given to you.

Dves just talk shit for the very same reason I am trying to simplify and summarize my still long posts in this thread. Cause in truth nothing is ever that simple. I have listed out some points you made and will just reply to them directly.

1. No one has said lowering rez cannot improve framerate. What we have tried to tell you that the framerate gains are so little that its not beneficial. Only time its beneficial is if you are having a hard enough time hitting your required framerate. Most devs will tell you that framerate is king and then you set rez later. Thats cause the framerate is directly tied to how powerful the CPU/GPU is and the engine has to be built to accomodate it from the get go. Dropping from 1080p to 720p wil only give you around a 4-10fps bump depending on your engine.That kinda bump is only necesary as a last resort. But yes, removing graphical effects would be a great way to increase framerate. But tahts not what you were talking about, and i had addressed this before. You are talking about dropping rez, and I am tellingyou again... the gains don't make it worth it.
   
   
2. No no no no and no. Dropping something that uses 5% of your CPU/GPU to 3% doesn't make it possible to make the CPU/GPU do 100% more work overall. I don't know how else to explain this to you but your obvious lack of understanding of this concept is why you are saying all this to begin with. When building a game engine, the first thing teh dev sets in stone is the games frame rate. Not the resolution. This is because rez is a very small part of the overall render pipeline. If a dev took a gme that was 1080p at 30fps and wanted to get it to run at 60fps... its resolution will literally be the least of devs problems.
   
   

why should consoles run at 1080p with barely any increase in clarity compared to 720p

It is just a few frames. And no, 720p wouldn't show a big improvement. That's not how it works, you don't just take the 10 and then double it. Diminishing returns. Also, the difference between 900p and 1080p is bigger than 720p->900p.

720p->900p gap = 518400 pixels

900p-> 1080p gap = 633600 pixels

Not to mention it still wouldn't be a 60fps regardless, as it would just hover between 30 and 55 instead of 30 and  45. Totally worth lowering the resolution.... not.

As i have also said earlier... memory bandwidth is also important. In the example you provided, if they checked the bandwidth used they would probably see that at 1080p the game ws also badwidth starved on that system. So dropping the rez, which also marginally drops its size in frame buffer allows it to fit with whatever mem bandwith the system had to give you better overall framerate gains. 

Even this loos example I just gave is very very very sparse cause as I said its never really that simple. You keep dropping rez to increase fps, eventually you get to a point where the bottleneck becomes the cpu or gpu. yu overcome that, then you get to a point where the bandwidth becomes the bottle nectk again. 

I just think your rpoblem is that you are attaching too much importance to something that isn't that power intensive to begin with.

The fact a game like the order is 1080p natively, and a game like ac unity is running at 1080p is all incredible

Is This a joke?? 1080p will always better than 720p. but i get your point for last generation or a weak console that cant candle both. Soon or later PS4 will be able to handle both. so at the end 1080p@60 with extra power is better.

Can you share your weed? I wanna get high too!

I have a 770 overclocked with more than 50% more VRAM bandwidth than the PS4 so memory bandwidth plus the heavily computation intensive TressFX enabled. This is the kind of performance difference you see from moving from 1080p to 720p