Kinda depends. I've made game jam games you can complete in like 10. Gravity Control takes maybe an hour? Give or take I never really speedran it.
My newest game I'm putting more time in I intend to take maybe 6-7 hours in total but it's years from completion.
The length of the game doesn't really matter though so much as the content of the game itself. You also have to account for people that just skip things, those that go into everything, etc....