Compatibility in terms of the Ring/Nest ecosystem would be the separation out as separate product categories, and prohibition against anti-competitive bundling of these four aspects: hardware device, backend storage service, client app (mobile/weapp) that interacts with both, and any background "application"" functionality (image recognition, sharing with neighbors/police, etc).
If Google or Amazon released a product in each of these categories that's probably fine, as long as each were only built with documentation publicly available to every other developer. The point is if Amazon storage + Amazon social features were still wildly popular-by-default leading to this type of commercial, people could easily switch to alternatives that respected privacy.