> Google partnered with Sonos explicitly to get access to their internal designs, and then copied them
If anything this ought to be strong evidence that the patents failed to disclose the invention and are invalid. Patents are a deal where you publicly disclose your invention in exchange for a temporary monopoly. If someone has to get access to your internal designs to copy them, they shouldn't be protected by patent.
Edit: (Note I'm talking about how the law ought to work, I'm not claiming this is strong evidence under current US law that the patents actually are invalid)
A recipe isn't patentable on its own, though. For most inventions you either need to demonstrate you have already built the thing, or have provided the thing to the PTO along with the application. For software, though, it seems you don't need to do either.
If anything this ought to be strong evidence that the patents failed to disclose the invention and are invalid. Patents are a deal where you publicly disclose your invention in exchange for a temporary monopoly. If someone has to get access to your internal designs to copy them, they shouldn't be protected by patent.
Edit: (Note I'm talking about how the law ought to work, I'm not claiming this is strong evidence under current US law that the patents actually are invalid)