We're starting to see a shift with the likes of Arkham Knight, AC: Unity, but I think it'll probably be a while before we see developers moving on from PS360 completely. I'm thinking that it'll probably be after this Christmas that we'll see a more definitive shift, as by that point sales on new consoles will probably be generally able to match last gen, as they're already pretty close now considering the massive install base difference...

When it's not possible to create the game they want to create on last-gen consoles.

LOL @ all the "stop development now" comments. Yeah, it's a brilliant business strategy to ignore a combined install based of over 160 million just so a handful of gamers can justify plopping down a huge chunk of change on consoles that offer a marginal upgrade in visuals over the previous generation of consoles.

What a brilliant business strategy this would have been if Sony and 3rd parties stopped supporting the PS2 as soon as the PS3 was released... yeah, that wouldn't have taken down a few more developers than what had already folded at the beginning of the HD generation. Or if then stopped supporting the comeback kid PS3 as soon as PS4 was released.... then it wouldn't have been able to claim "not last place" for the gen like it can now.

First off, both the PS4 and Xbox One have been out for half a year. Stopping to support the PS3 and Xbox 360 now would not be stopping to support them the instant the PS4 and Xbox One came out. Secondly, last generation was the longest lasting generation and frankly, many people are tired of that generation. I remember reading articles about how the last year before the PS4 and One came out that it was one of the lowest selling years for videogames.

http://blogs.wsj.com/digits/2013/06/17/videogame-software-sales-in-may-were-lowest-in-over-a-decade/
http://business.time.com/2013/02/11/game-over-why-video-game-console-sales-are-plummeting/

Finally, according to your reasoning, video game developers should never completely let go of old generations. What reason did they have to stop supporting the PS2 in favor of PS3 and Xbox 360, knowing that the PS2 has sold better than the PS3 and 360? Do you think it would have been a wise decision to continue supporting the PS2 just because of the large install base?

At a certain point, you have to move on. Last gen has lasted long enough, people have had enough time to save up for a current-gen console.

2015

When profit from game sales on last gen consoles are not significant enough anymore.

I have no problem with cross gen games as long as they are handled by small or up and coming studios. Basically, I expect any Madden, COD, or any other yearly franchise to recive zero new optimization year to year after the release of a new console.

Once a new console releases there should be a dedicated team that makes the yearly franchises, that focuses exclusivly on the new gen platforms.

As for exclusive or multiyear projects, I dont want to see any cross gen in those feilds. So Final Fantasy, GTA, Fallout, ect. I expect to be only on the most current gen consoles.

By the end of this year

I suspect that by the end of next year will be the major last year of last gen. Though I would prefer it to be earlier, they will definitely continue this and next year.

The sooner we have big titles on current gen only will speed up the process. But it will be judged on how many copies of each platform sell when they release the multi platform versions.

As long as publishers like EA and Square Enix post losses ANY profits are significant enough. Money was also part of the reason this gen was so long in the first place.