Does anyone seriously think Apple would, if true, install an "inferior third party" product corporate-wide? There are a lot of options Apple could do without fully purchasing 1P.
Why do you call it an "inferior third party" product?
For many of us 1P is much better than iCloud Keychain, even as a standalone password/information manager. When you add on the capabilities of 1Password for Families/Businesses, there is nothing in iCloud Keychain that can come close to the capabilities.
(Could Apple have an internal password manager solution that is better than iCloud Keychain and has password sharing capabilities, possible. But, why reinvent the wheel.)