Because games aren't priced based on how long they take to complete, surely you cant be serious here?
I'm being serious, you're not getting the point.
When I buy an RPG, I expect to be getting an actual RPG, with a nice huge world to explore, lots and lots of quests to do, and lots of content.
Elder Scrolls games are a great example of that. You can finish the main story line in around 30 hours, but if you want to everything in the game, it will last you for several hundreds of hours.
Theres also MMORPGs, such as guildwars. I paid around £100 for all the chapters, and have sank in over 5000 hours playing the game over almost 6 years.
Now then, a single player game that will only last 30-40 hours? Sure, £25 is ok for such a game if its a typical FPS, they never have hardly any content, and are mostly incredibly short and boring. But for an RPG to be that short with hardly any side quests or nothing to do away from the main story line to et extra gameplay out of it?
Wait, did I just say RPG? I meant a console derp ruined hack n slash game with no RPG elements at all.