It seems that the author is a theorist, not a practitioner, as his theorist insults ("Despite all the equations, it seems to me that your work didn't require any real mathematical sophistication. Did I miss something?") are much better than his experimentalist insults ("Wasn't all this done years ago at Xerox PARC?")
If you want to insult an experimentalist, it's there's a much more cutting one - "Didn't Microsoft do something similar when they were working on CORBA?".
Didn't Microsoft do something similar when they were working on CORBA?
To which you'd get a puzzled look while they condescendingly informed you that Microsoft never worked on CORBA - that was the OMG, and Microsoft had COM/DCOM.
Xerox PARC is good, because they probably did work on whatever is being discussed.
Other options include "Didn't Englebert include that in the Mother of All Demos?" and "Didn't Taligent have that running?"
If you want to insult an experimentalist, it's there's a much more cutting one - "Didn't Microsoft do something similar when they were working on CORBA?".