Hi NoNukes,
Before I address the above, and in the interest of full disclosure, I am an intellectual property lawyer. ...
And I am an intellectual property creator (I am a designer, some of my designs are distributed world wide).
I think the issue is muddied a bit by the variety of things that come under the broad umbrella of intellectual property.
1) Copyright last a real long time, ...
3) Trademarks and trade secret protection are not time limited.
To me a copyrighted name and a trademark are like a legal name, and infringement on the trademark is like identity theft (or do we get into considering a person's identity their intellectual property? a bit of a stretch imho - do we want to get into issues of naming babies violating another person's identity?)
My memory from 20+ years ago was (iirc) that Auto Mart was taken to court by Wal-Mart as an infringement on their name, Auto Mart lost and had to change their name to Auto Zone. This is ridiculous imho, as it would take a moron to confuse the two. What's next - suing all the grocery marts?
Just because a company in one part of the US chooses the same name as a company in a different area does not mean that they intend to infringe on the second company.
Identity is important for identifying the appropriate person or company, and nothing further. And like the names people have, we should expect some duplications to occur. Those of us with common names are very familiar with this: when I lived in Toronto there were 2-1/2 pages in the phone book that could have been me.
4) The duration of patents and copyright is fixed by statute, ...
Where we are talking about an invention (a better mousetrap) or a creation (art, poetry, songs), I think we need a new paradigm for how the inventor\creator is properly compensated and how companies can profit from them.
If we were talking an hypothetical free market scenario, the inventor\creator would be rewarded every time the property was used, rather than be limited to royalties (if they are lucky) from one company, and the natural dispersal of the property would indicate how valuable the property was: the more it was used by anyone the more value it has to society.
What I see with SOPA/PIPA is protection for the company profits and not for the inventor\creator.
Enjoy.