70% of the people don't finish their games? Could we also say that 70% of the games are not worth finishing?
I don’t think those two statement are relevant to each other. Most people who buy games don’t finish them - regardless of their quality. Pick your favourite games and go to steam achievements and see how story achievements aggressively decrease in percentage gained.
From what I gathered, if a game has a high completion rate, it tends to be a niche series with a very dedicated audience.
30% completion rate is actually pretty high. I think 10-20% is a more common number.