(ET) How do your batteries die?

[tbamc <tbamc gbta net>]

I bought a complete set of U.S. Battery batteries about 5 years ago.  
Only 1 of those 6 is still alive.  After talking to the  U.S. B. people, 
and this list, I think I should have been charging them harder/longer, 
but I'm not sure that relates to my question:

Every one of the dead batteries read about 4v when it expired, and 
couldn't be charged to much over 4v.  This implies to me that a cell 
shorted.  I would have expected the more likely scenario would be for 
each battery to just get weaker, i.e. still charge to above 6v but not 
hold a charge for as long.

Am I thinking about this correctly and is my experience typical, or not?

Thanks.

Thon