Seems its down to sweat.
Reports stil happening about this. But it seems to be players with more sweaty hands.
Players Complain PS4's Analog Sticks Wearing Down Fast
There's a strong chance the damage is caused by sweat though.
Over on Reddit a number of PlayStation 4 owners have reported that the analog sticks on their DualShock 4 controllers have worn down significantly since getting their console on November 15th.
It seems to be a problem affecting only some users, certainly both of my DualShock 4s look brand new despite a lot of use, and it's unclear how many players have been impacted.
If your analog sticks are starting to fray there seems to be a strong chance it's down to sweat and while there's not a whole lot you can do about that (aside from maybe being a little less excited when you play) there is a relatively cheap solution to prevent further damage. Amazon sells controller thumb grips from ProGamer in packs of four which, while designed for the PS3, should fit the PS4's analog sticks like a glove.
Of course, it's a shame if you're one of those impacted and hopefully Sony makes more durable, or at least sweat resistant, analog sticks for future DualShocks.
As you can see from the image above it seems the analog stick was grinded pretty hard against the casing of the controller and really, there should be no need to be quite so forceful - the DualShock 4 is a pretty responsive controller after all.
The DualShock 4 was designed with the input of major first person shooter developers.
http://www.gameranx.com/updates/id/19537/article/players-complain-ps4-s-triggers-wearing-down-fast/
