It seems like a sign of shallow gameplay/mechanics. Supreme Commander, Master of Orion 2, Knights of the Old Republic, Dragon Age (kinda), Mass Effect... Homeworld 2. You could spend - I'd guess at least a hundred hours or so - playing each of those games to see all their content and play around with all the options they offered you.
Story seems to have become a sort of distraction from the things that make a good game. So the story can be told in ten hours - what about the fun potential of the rest of the game? How many times am I going to play the thing? How much enjoyment can I extract?
Even RPGs, where a good story is important, most of the time is spent on quests and character interactions and on playing around with equipment and stats and so on. If you're just speedrunning an RPG's story, it doesn't generally take long. It's the game around it that takes the time.
At the end of the day, I'm not that interested in being passively entertained with the story. Maybe if the stories were better it would make sense as a form of passive entertainment. But games are like movies these days, and movies these days tend to have stories that aren't worth watching. If I wanted a good story, I'd go read a book or fish out some DVDs or something. I largely buy games for the stuff that goes on around the story, the game part of the thing.
Heck, at £3 an hour I could go and sit in a cinema for 10 hours at a comparable cost. £30 is like - I could buy 6+ hours martial arts practice, or go and do some archery, or go canoeing, or buy the materials to make myself a new desk, or.... £30 is not an insignificant amount of resources. It's not clear to me that the pay-off even makes sense anymore - though it did for things that you could play with for longer.
10 hours strikes me as ... there's probably not a lot there to play with. How many toys of any complexity are your bored of a mere 10 hours later? It may be a very polished experience but, how inventive can you be? ... I like finding tricky combinations of things and actually playing with stuff.