Because it means you pay more for something you don't want?
Adding extra things to a controller increases the cost. Companies are going to pass that increased cost on to the consumer, so you're paying more for it. Paying more for something you don't want is a bad thing. If you cared about options then you'd want it as an alternate controller so those that want it can have it, but those that don't want to waste money on things they don't like aren't forced to pay for it.
PS4 controller has a speaker, light bar, headphone jack, touch pad, internal battery, and motion controls.
In 2013, it cost exactly the same as an Xbox One controller that offered none of this.