Ps3 was released in November 2006 and attained  the age of 2 years and 3 months as of  February 09', Psvita was released  in December 2011 and became 2 years and 3 months old as of April's first week '14 and Ps4 was released in February 2014 and  reached its  second year and 3 months in the end of May '16.

PSV VS PS4 LAUNCH ALLIGNED COMPARISON:

UPDATE: 2 years, 3 months and four weeks!

PS3  2.9m   http://garaph.info/weeklyoverview.php?week=2009-03-26 17k

PS4 3m http://www.neogaf.com/forum/showthread.php?t=1237770  22k

PSV 2.87m http://www.gamefaqs.com/boards/620272-playstation-vita/69217569/http://gematsu.com/2014/05/media-create-sales-5514-51114 +17k

Important element:

PSV has sold 5m as of May 2016,  that has been sold within four years and 5 months....

PS3 has sold 5.1m as of April 2010,  that has been sold within four years and 5 months....

They have sold nearly the same in both time frames, while ps4 in two years and 3 months has sold approximately the same with psv and ps3, hence  it could be surmised that PS4 would have sold 5m in its 4th year and 5 months, if it fails to come close to it by then, it would be worrying ( notably for those who predict approaching/outselling ps3), barring any shocking unforseen circumstance! This year is very important and  indicative for ps4 lt sales...

P.s  I wanted the comparison to be between sony only systems, those that  fit in the comparison!

I don't think the problem for the PS4 in Japan is so much about Japan preferring handhelds as it is about the West dominating the console market so much. Few Japanese third parties can compete with the budgets, and they're relying on a more limited install base. Only thing I could see really helping a console succeed in Japan is if the Chinese home market expands greatly. May make Eastern style games more viable.

That's an interesting comparation.

There aren't many people expecting the PS4 to outsell the PS3 in Japan, so don't think there will be much worrying when the PS3 pulls ahead.

Oh thanks you so much mio fratello! ;) However, going by the views and posts number, I don't think that many people share that view,  to such an extent that I had forgotten that made this thread! lol

TIME FOR AN UPDATE! :)

Neo should help push ahead .