Because they are valuable, companies feel the need to use them. Disney still haven't made back what they paid for Star Wars, so they have no choice but to set the sludge pump to maximum.

Retarded. They would still be valuable even without individual companies having a monopoly on them, and in the specific example of Star Wars they have never set the sludge pipe to maximum, they got scared off of that idea before they even had the chance to try it thanks to how badly the sequel trilogy bombed. The initial plan was yearly movie releases presumably with the hope of going the marvel direction and increasing that output to at least one movie per quarter but after TROS it's taken them over a decade to get the balls to put another release in theatres where the numbers are metrics of success are more well known and publicly known.

The cost to register is $1. The anual cost to renew, however, doubles every year.

With registration costs that low you're basically encouraging patent trolling, and the compounding costs would hit failed indies the hardest. lets say you're only on year ten after release of an e-book or a game or something, unless you're already established and successful then the costs of keeping ownership of that IP will already cost more than it's worth.

Now lets look at this from the consumer perspective, Would you pay even $15 for something that you know will be free in just a couple years? Unless you expect to die before then I imagine not unless it's something that you are really eager to experience. It would create a mentality among people that everything created by a common man is free while only products made by multibillion dollar corporations need to be paid for because their IPs are worth enough to keep paying for the holding costs for 30 years without it being even amounting to 1% of original production cost so they will be able to hold onto their IP for ungodly long periods of time.