If they can easily fix it, why has no one fixed it? It's an issue that's inherent with Lithium batteries. Heat and over-cycling shorten the overall lifespan of the battery. No one has figured out the solution to this yet.
If it's plugged in all the time it's not cycling the battery. It's resting at 100%. If frequent small discharges/recharges is a problem you can let individual cells take turns discharging. I'm pretty sure battery problems of this sort are apocryphal at this point. I'd change my mind if somebody who worked on them told me otherwise.
