Battery life: why don't manufacturers care?

Battery life seems to be a much discussed topic, both online and in real life. It seems to be one of the main complaints from Android users. I don't know how many times I've heard "I'm really satisfied with my device, other than the battery life" I fall into this category as well, being a user of a GSM GNex. All of my previous devices have had the same shortcoming: HTC Hero, EVO, Sensation. I actually believe that HTC is the biggest offender of releasing devices with abysmal battery life.

I just don't understand why this concern has gone unheard by the manufacturers (with the exception of Motorola). The only devices that I have ever heard about having good battery life would be the Maxx, and Note2 (which only has a huge battery by default due to its size). It seems so silly for new device features to be added from one generation to the next only for users to deactivate them to be able to make it through a day. I would certainly be in the market for a Maxx if it wasn't a carrier exclusive. It doesn't seem to make much of a compromise in form factor, just being mere millimeters thicker than the Ultra. Why haven't other carriers released devices that are similar? I'm hoping that the philosophy of the development of the Moto X will bring about some change in the Android device market. I'm willing to make some compromises in size, screen, and spec sheet if the device runs smoothly and is able to make it through a full day. Who else feels the same?

Just burned through 10% typing this post....