17000 endings came from the same place as the 175 hours of cutscenes. It's just hype and bullshit in order to get the anticipation up to fever pitch before the release. Stay calm.
I wouldn't go so far as to call it "bullshit" more like "puffery" - I think that is probably an accurate number if you count all the final ending permutations but the overarching ending are probably in a more reasonable 10-20 range.
There are probably also some secret ending outcomes that contribute to the main ending in various ways.
The point is that there are way more outcomes than we may realize.
Look at it this way, at 2,000 hours in EA I still find new stuff, mainly reactions. I was 1,500 hours in before I discovered you could
Torture Rugan to death, keep the chest, and be on good terms with the Zhents if you did things a certain way.
I was 800 hours in before I realized you could
get the Druids to complete the Ritual and close off the druid grove if you kill all the Tieflings.
It was 3-4 playthroughs in before I even found the Kuo-Toa...
