Half of 360 sales are in NA. It's 1/3 for PS3 and PS2.
As PS3 does not have tail in NA, I'm sure 360 does not in other countries.
PS3 tail would have to be *huge* in the rest of the world to overcome that kind of 25:2 ratio in the US. And I wouldn't bet that PS3 has that much of a tail anywhere...
Sony were keen to move away from the expensive to make PS3 and onto PS4, which was the right move for them. At the same time, the 360 has many advantages that make it more valuable to MS to continue pushing.
- 360 is much cheaper to make (no blueray, 32nm SoC instead of two 45nm chips, only 4 memory chips, no Rambus, doesn't use an nVidia part [lol])
- Cheapest HDD-less 360 version isn't effectively crippled
- 360 has a decade of superior 3rd party games (from cheaper to manufacture hardware)
- Remaining 360 3rd party games will continue to be superior
- 360 online community is still strong
- MS have an interest in continuing to cultivate 360, especially as Xbone is getting hammered by the PS4
Relative to sales during the generation (which is how you would gauge a "tail"), I expect the 360 to have a better tail in just about every market it's in. Because it's far, far better suited to it.
Similarly, I expect the PS4 to have a better tail than the XB1: better hardware, better games, stronger game-focused initial concept, and MS will want to put the XB1 hardware behind them.