That's exactly the issue that the previous poster brought up -- with a patent, the "secret sauce" is public. The lessons learned by Google all need to be re-learned again and again, which slows progress for industry as a whole.
In the pharmaceutical case, generic manufacturers are often able to start producing a medicine on the day the patent expires. In the Google/trade secret case, the world may forever lose valuable tools and techniques that are kept proprietary once, but cease being useful to Google.
It seems the usefulness of this varies from field to field. It's generally easier to reverse engineer software from binaries or even rewrite it from a plain English description than it is to reverse engineer the patents.
Whether it "slows progress" has got to be an empirical question with results that vary from field to field. The "with patents" case in software forces not only rediscovery but reinvention and engineering around patents (which exists in the pharma case as well).
Now, a software patent system that involved filing a copy of the source code with the patent? That would be a great way of preserving tools in the public record. But that's not how it works at the moment.
In the pharmaceutical case, generic manufacturers are often able to start producing a medicine on the day the patent expires. In the Google/trade secret case, the world may forever lose valuable tools and techniques that are kept proprietary once, but cease being useful to Google.