When Apple had clearly stolen the look and feel of Delicious Library to make iBook. The author was a "small company". He even show some happiness that his work was used by Apple.
The point is, he couldn't have sued Apple. Simply because, actually, a small company could certainly not win over a big one. The big one will use a lot of money to keep the trial as long as possible while continue to steal your stuff. Even if won, it would have last too long to save your business. And you had lost a lot of energy. This remember me the medieval justice were the richer always win.
Actual patent system only give an advantage to big companies. What if big player start to sue small startups because they used the double-click, the swipe, a wood texture that looks like a library?