It would be a very simple software (firmware?) update for them to be able to support ePub. Then ALL devices would support ePub (or at least the ones that matter...)
Amazon just chooses not to.
"Gnihcnip" - the act of "reverse pinching" to expand/zoom. Pronounced "Niknip" (the "g" and "h" are silent).
"Live long and prosper." ~ Spock
"What's that goat doing up in the clouds?
" ~ Pilot