That's a rather poor example, because patents are not and never have been issued in perpetuity (at least not in the US - I can't speak for ancient Greece).
The whole rationale behind granting of patents is that there is an explicitly-stated trade, which is intended to benefit both parties, the inventor(s) and the public - the "founders" clearly understood that, and the passage of time has not invalidated that understanding. The inventor gets an exclusive, for a limited period of time, during which time he can prevent others from using the patented material. In return for that, the inventor must fully disclose the invention to the public. So, after a period of time goes by, the invention is in the public domain. That's very different from locking something up in perpetuity.
Copyright is quite a bit longer, but copyright laws are entirely different from patent laws.
My objection to the Eolas patent is that it was wrongly granted - there is prior art which should have invalidated it and prevented it from issuing in the first place. I suspect that another round or two in court will settle things. I also suspect that Eolas believes that to be the case as well, and so they are going to try very hard to milk it for hundreds of millions of dollars as soon as possible, in the hopes that they can grab a windfall before their patent is invalidated and it becomes worthless. Not all that different from the "take the money and run" philosophy behind the SCO-Linux dustup. IMHO it's only a matter of time before both of them get their comeuppance.
Copyright has been extended over twenty times, the last time so Mickey Mouse would not go into the public domain.
The same thing is going to happen to patents.
There is no difference between eternal copyright/patent and extending the term every time one is about to expire.
When you have the Patent Office granting patents on double clicking an icon to make a purchase, the abuse has reached an apex and it is time for the party to be over.