More generations than not have shown that the power leader in home consoles tend not to win that particular generation (total sales wise).  The PS4 is well on its way to break that tradition.  The key word is how?

Is it the power/value proposition?

Combination of 1st and 3rd party titles along with the global nature of the Playstation brand?

Is it really the missteps by its main competitors, or maybe its just the PS4 time?

1. Goodwill.
2. Respecting gamers by standing against DRM.
3. Powerful system at a cheaper price.
4. Playstation first party track record.
5. 2008-2013 support for games rather than chasing casuals / non-gamers.

Price, popularity of brand, not calling us thieves.

I think the brand name is still pretty huge among the populace. Playstation 1 & 2 dominated, and if the PS3 wasn't priced so high it likely would have too (at least more than the extent it did).

1.) Not disrespecting the consumers
2.) Established reputation of making high quality 1st party exclusives
3.) Transitioning into this gen without abandoning the PS3
4.) Making the most powerful console that is also easy to develop for
5.) Price per power

We are more connected than ever, Facebook and Twitter are now ubiquitous, so the 8th gen is more social media affected by a landslide than 7th gen was. So PS4 policy and technical superiority was knowledge that spread like wildfire despite traditional media downplaying it to the hilt. Simultaneously, bad PR and poor policies sunk X1, because bad news is spread instantly far and wide for FREE, while trying to fight city hall from a megacorp perspective means spending hundreds of millions on advertising that may not be nearly as effective. In the end, the consensus of trusted friends and family of gamers outweighs corporate advertising this time around.

Don't these threads get old?

Its simply the best console out there

Best price vs performance on a console
Best first party track record.
Biggest brand recognition world wide period.
Current PS3 vs Xbox 360 vs Wii sales. Last gen consoles are performing at the same relative pace of current consoles.

PS brand and they did, still doing, everything so perfect when it comes to marketing along with word of mouth, makes me think that PS4 will win this generation.