Why DRM is different to Physical Incompatibilty

Imagine this.

You want to buy a water filter jug. You like the (say) Brita jug, because it's just the right shape to fit in that empty space in your fridge, but their replacment filter cartridges are more expensive than (say) the Kenwood filters. And the filters aren't compatible. So either you compromise on your choice of the main item for the sake of cheaper consumables, or you are locked in to expensive replacementsfor the sake of the initial investment.

Now go one step further. Imagine you want to buy a printer. The (say) Lexmark prints very well, but the cartridges are expensive. The (say) Canon has cheaper cartridges, but isn't as quiet. The cartridges are slightly different shapes, so you can't buy the Lexmark printer and
the Canon ink. Again, you have to base the initial, long term, investment on the the price of the consumables. After all, when your first ink cartridge runs out, you're more likely to buy more ink than another printer.

But lets take it another step. Say the physical ink cartridges are compatible, since it's a generic plastic casing. But the printer manufacturer has some code in the printer that interrogates the chip on the cartridge to find out if it's made by the right manufacturer, and won't let you print if it isn't.

A small step further: you buy a dvd player, but that restricts your choice of dvd providers because of the region encoding. And in this case you don't even have a choice - if I live in South Africa, the dvd player I buy there will be encoded for that region. If I then want to buy some dvds that aren't available there from Amazon, I can't becausethey're encoded for a different region.

Now think about music. Maybe you like the iPod, but music available on msn is cheaper, or there's a wider range. Again, you're locking down your choice of future suppliers by your choice of player, sinceDRM schemes are not inter-operable.

In the case of the water jugs, it wasn't so bad. The jugs are fairly cheap (compared to iPods, anyway) and unless you buy a couple of dozen filter cartridges in one go, you won't be losing much if you decide to switch your investment (the jug) to another supplier. So while it might be nice if all the filters were compatible, it's not something that would be worth mandating by law.

But with the dvd player (region encoding is just another form of DRM) or the mp3 players, it becomes an issue. The initial investment is high, but the bigger investment is the future purchase, the music and the dvds, since they aren't consumables. Switching supplier means
losing the entire investment, both the initial one and the investment on building up a library.

People arguing for DRM often use comparisons with physical objects to show that enforcing interoperability is ridiculous. Why shouldn't a car manufacturer specify that only their genuine, proprietary parts be used as replacements? The answer is that generally, in the physical case, the initiL purchase is the major investment, and any future purchases are consumables, meaning that the cost of switching is limited to the initial investment. Whereas with DRM, the cost of switching is both the initial investment plus the non-consumablefuture investments.

Update: Here's a further analogy, though, using the physical analogy the other way round this time. Suppose that water filter cartridge almost fitted in the other jug, except for one little piece of plastic that didn't contribute anything to the functioning of the cartridge, and was there purely to prevent it from fitting in any other jugs - that's DRM. Then imagine that there was a law to prevent you from filing off that piece of plastic to make it - that's the DMCA. Seems silly, doesn't it?