There are full-featured electronics with color screens, fast CPUs, and all sorts of other stuff.
There are small electronics that are quite portable and don’t weigh much.
There are electronic devices that have a battery life longer than handful of hours.
No device yet combines all three of those though. You want a laptop with long battery life? It will be slow or big and heavy. You want one with long battery life? Either ditch the color screen or carry a sidewalk brick full of electrons (a.k.a. “big battery). It’s all about sacrifices, and it will continue that way for the foreseeable future.
The Kindle Fire is designed to be small, light, and full-featured. Ditto with every other tablet/e-reader that doesn’t use a monochrome e-ink display.
FWIW, my wife hated when we upgraded our phones from Samsung Trances to Droid; now we have to charge every day (or more with heavy usage) instead of twice a week. Such is the price of progress.
@WillWorkForChocolate If you want days instead of hours, ditch the color. Otherwise, get used to the cord.