As for these points...
"Related is the fact that the sales for the twins in the US exceeded by far the sales of the PS2:
twins total in US = 76M vs 53.65M for PS2."
1) You never read what I wrote properly. I attributed almost half of Sony's marketshare loss to Microsoft since the numbers came up to that. The last bit went to the Nintendo Wii.
2) Japan's interest in the console market is dwindling. They are mainly focused on handhelds.
As for this...
"Another thing, the latest argument for TLOU:R is that many PS4 fans don't own PS3s. If that's true, then it seems like there is a lot more movement than we like to think. Some start gaming, some stop, we really have no idea what happens to owners between gens."
That is true for any console. Only a portion of the crowd buys the exclusives. Rarely is it ever at extremely high percentages attached to console sales like the Wii Sports bundles. Wii Sports was the game every non-gamer and their grandmother wanted to play.
It still doesn't explain the regional numbers in light of your theory. In US:
How does half of PS2 (53.65M / 2 =~ 27M) become 47.25M (Microsoft's marketshare in US)?