not because the series wasn't renewed for a fourth season. because of the content of the final episode in particular and through retrospection the majority of the content of the entire third season and through retrospection large portions of the content of the series as a whole.
unsatisfying is putting it too mildly -- some people may have found the ending of lost unsatisfying. in some respects.
utterly unsatisfying. (begging your pardon.) insultingly, disturbingly, and destructively unsatisfying.
there was foreshadowing and outright promised plotting based on plotting depicted.
and no comeuppance. no delivery of the promised goods.
it's a simple bargain we the audience demand fulfilled: don't set up what you won't pay off.
if emulating shakespeare, how to have refused the dictum that everyone dies in the end?
and not merely the plot but the characters who wandered in and out of character throughout the third season (it was bad enough in the past but jumped off the cliff of no return when al capitulated to the figurative castration through the literal removal of an analog).
i should have known then but assumed that we were being given mere delay to cater to the reality that tv drags out storylines that movies complete in two hours through endless slogs in multiples of dozens.
for all of the fantastic things that it did including the ones not to be found elsewhere, the show had copious flaws, and being a creative endeavour that painted itself into corners due to having failed to account for the limitations inherent in its unrelenting adherence to historicity proved to be a fatal flaw. i will not cease to love portions of it but the whole i can have no affection for.