If patents really rewarded invention, that would be good. However, in the current system, when many people independently come up with an idea, only one person gets rewarded by the patent system. All the others get sued or have to pay licenses, and lose all the benefit of their work, even if they did come up with the idea themselves.
This discourages invention, as it is practically impossible to create anything without infringing some patent; to the point that even when an outfit like Google deliberately attempts to create a royalty-free codec, they seem unable to do so.
In a proper system, when people independently come up with an idea, the benefits would be shared between them. Many people having the same idea means the idea is less original, and so should be less rewarded.
Another problem is that fighting a lawsuit is so expensive that even big players like HTC and Samsung have an advantage in licensing a bogus patent rather than fighting it. Never mind small players like Compal Electronics...