I can't think of many devices of this nature that I have used past 3 years. In that span, there is usually a process shrink, battery advancements, and fundamental science breakthrough that happen which convince me to upgrade. We've got batteries in the lab that charge in 30 seconds to 80% capacity right now. Nano-Structure use in batteries is changing the field dramatically.
People are starting to take for granted the tech shrinkage that is taking place. The phone can't get much smaller or it'll be to small for human hands; instead more capability will be crapped into the same amount of space. Circuits are so cheap, we have them in talking greeting cards and then throw them away.
So I don't mind an integrated battery as long as it performs until I replace the device, which at this pace, is likely less than three years. At which time I'll get my hoverboard/reader/food replicator combo device, and it's integrated battery, and replace it later when I can get the phaser option.
With the logic used here, no one would have bought a Model-T, which would have deprived us everything that followed. This device is aimed at businesses, just like the first SSDs, and from those big pockets, the R&D will be paid for, after which time regular people will get them for the manufacturing cost plus some profit margin.