If that were actually true then they would have already...new code yes, better code no!! Additionally, new code builds on old tested code, so new code that would not infring on Lang would take considerable time. Lang actually captured the essence of search logic now used by GOOG and others...read the patent to understand the search and sequenceing of seach term.
Dont write things if you dont understand it was the system not the code #$%$ thats why Jury went with Lang the creator the key isnt in the code its in the system. Google can give Viringo adwords and create there own system we would be happy owning google adwords