Which part of the OP or anyone elses' posts is this a reply to? Nobody is saying the PS3 is a failure but they are saying it hasn't made a comeback.

Please look at the graphs, they show a slow start and building up over time, those graphs don't show a "comeback", they show an improvement.

sales = consistently progressive
pr / attitude towards the ps3 = comeback over the past 4 years

there, solved your confusion over the ps3's comeback - in order to maintain its sales the machine had to make a comeback in 'the hearts and minds' of potential customers, and the sales data shows that it made this comeback by maintaining a steady climb despite the initial frosty 2 year attitude towards the system when only sony diehards or those with money to burn were buying it. 

Right now attitudes toward the WiiU are frosty and sales would seemingly be bad because of lack of games but aligning wiiu launch with the 360 and ps3 shows it isnt actually doing that bad, yet when nintendo release a bunch of games and said games sell well, just like any other console after a major game reease hardware sales will spike a certain degree and the general mood of doom toward the console will change (hopefully), in that regard the WiiU would make a comeback, changing peoples attitudes towards it and watching the sales steadily climb, and thats exactly what the ps3 did despite its market position, price, 'ps3 has no gaems' meme and other stuff, so that should answer your question, focusing on sales data alone does not give you the whole picture.

whats this "we " business?

this thread isnt saying its a failure.  Not sure where you are getting that from?

"We" as i'm a Sony fan, i'm not denying that. But from the atmosphere in this thread, it just sounded like people said PS3 was a failure at a glance. I actually had a second look at the graph and now understand where it isn't a comeback but it is still an achievement that it has almost caught up with Xbox 360 despite the not so great sales at times after launch. On the other hand, if wii u started selling like PS3 does at christmas that might be a comeback for Nintendo, thats something for us to see years from now, maybe.