I think the hours you get out of it is a valid component of the value you get out of a game, but it's trivial to make a game longer, and a tight 5-10 hour game can frequently be more valuable to me than a 70 hour game, a lot of Capcom's games among them. Part of the reason Suicide Squad and Skull and Bones are getting slammed in reviews right now is because they made games that could be played for hundreds of hours, and that happened at the expense of making great games that you'd be done with in 15 hours. When is the last time you bought a movie or went to the theater? I'll wager a guess it cost you more than $3 even if it was really long.
And all hours are not created equal either. An action game that takes 50 hours would probably be exhausting, but a turn based game like an RPG or a 4X would feel right at home there, since you're spending a lot of time in menus making slower decisions.