What is DRM ..really.. all about?

I see a lot discussed on the net about DRM and its purpose. The default answer is to stop piracy. However this cannot be true since pirates download cracked versions that bypass all DRM.

Now I myself would never do anything illegal of course, but I'm sitting with a 24/2Mb broadband connection that could in theory download a full game from a bit torrent site in about 6 hours on average. Which is faster than ordering on Amazon, or finding time to go into town to buy a copy off the shelves.

It might in theory be an attractive route to follow, since the way DRM is heading you can only rent games rather than buy since they only let you install a fixed number of times. (There are certain enlightened companies that offer a cheap and very fast digital download, coupled with regular updates and a secure system of logging what games you own that is actually far more convenient, safe and reliable to use than even a bit torrent!)

I suppose my perspective is that of a cash rich/very time poor office worker. Maybe in modern schools one kid will buy a game and pass it round 70 mates to copy? So in this case it would make some sense. But otherwise we know that it’s nothing to do with torrent piracy, we also know that these corporate types are actually smart, so they must know this too.

What do you think the real reason for oppressive DRM? The most compelling reason I have heard is it’s actually more about limiting second hand sales and giving a game a fixed lifespan rather than piracy. Furthermore it’s not really the developers who want it, it’s the distributers (i.e. EA) because if you can only install 3 times on average you’re not be able to use it after a few years (I think I have reinstalled Starcraft about 10 times in the last ten years). Also if the DRM is oppressive you can't buy a second hand copy. So if you can't play your old games and you can't buy cheap second hand games you have to buy a lovely high margin new game.

The second reason which I find compelling is the internal pitch idea. I used to be an investor on behalf of what you guys would call a mutual fund. When a company comes to pitch for investment or indeed a division internally to their own corporate board. They need to be able to answer any concerns the investor/board member might raise. Your typical investor/board member are in their 50's, they are smart guys and aware of, but not savy, on latest trends. So they know about piracy, but are not quite clued up on how exactly it works in practice. So when a department head wants them to green light something they will ask about piracy. Now picture yourself as a middle manager being asked this questions....
You can say a) Yes we are using the latest protection to safeguard our IP.
Or you can say Its won't help anyway, so lets just spend that money delivering content and updates so that a smaller percentage feel inclined to pirate.

Now fast forward 2 months after launch when the board gets a report on the projected lost revenue due to piracy. If you answered 'a' they will ask what is wrong with the protection, if you answered 'b' they will ask you what’s wrong with you!

I found an interesting case study is Mass Effects. The toughest DRM to date, an excellent game, ruined by DRM. Both here and over the pond in the states it scores about 2.5/3 on Amazon, where it should easily be 5 stars. After only a few months on sale the price here has crash from £34 ($68) to £20 ($40) as retailers can't shift the stock. Now I appreciate it’s a lot easier to provide additional content for a game like Sins than a story based RPG like Mass Effects. But still, the harm has been done.

So what do you guys reckon. Is it a conspiracy Against their paying customers to  get them to buy new games more regularly, fostered by evil EA?
Is it a case of misunderstanding and ass-covering by middle management?
Or do they really expect that an encryption put together by 7 guys with a PhD in computer science can't be cracked by 200,000 15 years olds a few days after release, only to be genuinely surprised when it does happen?
Or is it really something else altogether?