Re: He does have a point
"Your arguments, while seductive, are just plain wrong. It does not matter if J.K Rowling had it bad and now is a billionaire with copyright but would have just been sad without it "
Except that your original argument was that it didn't create wealth and only leachers benefited, so it does matter in that it destroys the credibility of your argument.
" It does not make the world a better place and hence it does not serve its function and hence should be withdrawn."
That's a bald assertion you make. For a world where authors and artists and composers are not payed by wealth patrons, but by people buying copies of their work, it clearly serves to help return money to the content creators. Is the system perfect? No. Are the ever-lengthening copyright periods detrimental yes. But you haven't yet proposed an alternative system for funding easily copyable creativity.
"The rent-seekers who profit from it, a handful of superstars and their heirs who profit, plenty of creative dupes who have no reasonable hope of profiting from it *ever*..."
... and of course all the small-time photographers who would see their work used, un-paid by the Daily Mail.
"There are very few 'inventions' that are very inventive and useful in the patent system. If there were, teams of us would be poring through patents looking for neat stuff. "
Which lots of people do. Again, is the patent system perfect? No it's become distorted and the quality of patent examination and awarding appears to be horrible. That doesn't mean that the entire patent system is without merit, just that the award of patents needs to be tightened up.
You might not like copyright and patents, but you've yet to make a sound case for them being abolished.