If DPC has indeed said that 10 episodes is a possibility, then I can think of 2 reasons why they might be saying this:
- They're purposely condensing the story in order to make less episodes than initially speculated, possibly due to burnout, not wanting to spend so many years on this one game, or they have another game idea they want to start developing.
- The condensing has simply happened naturally as they've developed the story and realised they don't need as many episodes.
At the end of the day, as much as I'm sure we'd all like to see this game carry on for 12, 16, or even 20 episodes, we have to remember that this is one person making the game, and if they don't want to spend the next 4+ years working on this one game, then they don't have to if they don't think they need to.
The fact that Ep 6 is so huge and promises 4-6 hours for completion of one playthrough makes me think that we could be getting 2-3 episodes worth of content condensed into 1 and could mean that we'll get less episodes than anticipated.