Think it through:
> enforced separation in law between commercial application providers and storage providers. So, if someone writes an app like Google Docs, they can't just store the data opaquely on their own cloud servers. They legally have to integrate with a separate storage provider.
Now, is the law going to mandate the exact API as well?
The likely implementation of this is that, just as every app developer copies every other app developer, when choosing which User Storage Backend to integrate with, they will pick the most popular one, or a near competitor. AWS, Azure, or Google Cloud. (Apple-focused developers may choose Apple Cloud; I'd expect Facebook to spin up one if this became law too).
Just as you don't get general-purpose OAuth integration so much as "log in with Facebook / Google" buttons. Those are your two choices.
Yes, the original intent would be targeted at Google and Microsoft, which currently own both big web apps and big cloud platforms to run them on. I'm not convinced that splitting them vertically would stick; the convergence effects are very strong. So you end up with (choice of two office suites) x (choice of two backend providers), big deal.
Is it sufficient that Google Cloud Storage would have a separate stock ticker from Google Cloud Apps?
It reminds me of rail privatization and the nonsense of having thin shell companies run the trains while leasing all the rolling stock from a couple of companies and running on tracks owned by exactly one company. It didn't really expand choice and it provided plenty of opportunity for blame deflection.