The cost wasn't only with consideration for the battery. The touchpad is going to add some cost. That speaker/microphone is going to add some cost. The LED illuminated panel will add some cost. The unannounced features would add cost. The extensive wishlist of features someone was hoping the controller would contain would add some cost. Etc.
Yep - certainly true... It will certainly add cost, but I suspect a more accurate suggestion is that it would "reduce profit" on the controller rather than necessarily require a price rise.
e.g. AFAICT the price of a controller is mostly independent of the actual cost of making that controller:
- the price of a dual shock 3 was $55 at release.
- the price of a dual shock 3 ~5 years later, is still $55.
- an "unbranded" version sold through the same retail in 2013 is $20-$35.
I wouldn't be surprised to see the same price as the DS3 or e.g. +$10 if they think the xbox controller price is going to increase.