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Harry,
There has been 2 primary development directions for batteries, such as Lithium Ion based chemistry. A lot of electronics batteries have been pushing for the maximum capacity in order to provide the longest runtime. One of the tricks for increasing capacity involved using thinner separators. It is shorts caused by broken separators that caused those fires and other accidents. So the end results was higher capacity and more fragile batteries that would not last very long. This problem was made worse by having devices like laptops drawing a lot of power (due to bigger LCD screens and more functionality like WiFi). The end result is batteries that last only a few years.
So your statements is correct regarding this design approach. Even so, they can last 5 and 10 years even when power draw is lower, such as eReaders. I fully expect our Cybook batteries to last 10 years, probably more. So while lifespan is limited, there is a big difference between 2-3 years and 10+ years.
More recently the new Lithium chemistries are being developed for power tools and cars. These sacrifice some capacity (lower) for a much more robust design that lasts much longer. So for instance GM Volt car demands that its batteries last at least 10 years, while supplying much higher power demands from a car. These should easily last 10 to 20 years.
So while all batteries do have a limited lifespan, they can differ a great deal. Some people reported their 20+ year old NiCd batteries still working!
What I was trying to say that there is again a tradeoff being made. More functionality causes more power draw that both reduces battery runtime and battery lifespan. Personally I prefer that device designer is more selective about functionality. Most makers these days just keep putting in more and more and couldn't care less about battery.
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