Point one is ridiculous because it assumes that 1) movie prices should be $10-15 and 2) there is a direct relationship between movie and game prices.
Movies require a large investment of capital on the part of the middleman (projectors, screens, 3D tech, etc. that all have to be updated every few years). Games require none of that. Only big budget "blockbuster" movies are only available at $10-15. Smaller titles can frequently be found at alternative theaters for much cheaper prices.
Much of the replayability in today's games comes from user generated content, which requires only the creation of the tools necessary for players to create their own content. In the case of FPS, the replayability really comes from playing against others. Every match is different. All it requires is the design of maps and modes. In this sense, creating hours of content is easy (unlike in singleplayer only games).
My three favorite games at the moment have all let me put in more than 25 hours. I'm already planning on doing another run in ME2, so that should be good for 50 hours or so. GT5 is going to have hundreds of hours devoted to it by the time I'm done. Counter Strike: Source is older than this generation and is a perfect counterpoint to "too much of a good thing. I've devoted almost 400 hours to it over the last couple years.
For a single player game to be worth it to me, it needs to either be 10-15 hours long and awesome enough to want to replay it more than once (i.e. HL2), or 20 hours long and pretty good. Then, you get gems like ME2 and LoZ games that are both long and so amazing that you'll play them over and over.