People try to justify it, but it was a total cop-out. From my perspective:
1. The writers had an amazing 3-season story
2. It got popular & got extended to 6 seasons
3. The ending was garbage
People can make all the excuses they want, but it just wasn't a truly fulfilling ending. To me, you have to be
very careful about doing a huge build-up, because if you don't have a meaningful payoff, then it leaves a bit of a sour taste in your mouth.
Some good answers here:
The US television drama Lost first aired in the United States on September 22, 2004 with the most expensive pilot in TV history.
www.telegraph.co.uk
I remember watching Heroes after Lost and feeling so satisfied that they gave you answers in a reasonable timeframe.