This thinking right here, sounds like a reason why Google retires a lot more services at much higher frequency compared to other companies?
In https://thehftguy.com/2019/12/10/why-products-are-shutdown-t..., the HFT guy brought up the "5 years upgrade pain" as the reason why a service would be retired, at the time when the pain from upkeeping outweights the gain from revenue.
By regularly making backward incompatible API change, as afforded by the monorepo, while also having engineers moving freely between projects, the upgrade pain cycle becomes way shorter for Google services.
By the way, this line of thought also leaks into public facing source code, with guava being the poster child of breaking backward compatibility, althought it has learned its lesson starting with version 21.