I agree with everything, except with the last sentence here.
What is the distinction between “data” and “content” here? Is there a clearly agreed upon definition of data and content, or even a legal one, that can be evoked here?
Some jurisdictions, like in the European Union and in Brazil, do have a sui generis database right, so that could be the one governing data, while copyright governs content. Some licensing schemes like Creative Commons attempt to cover all grounds in a single license.
What services from Big Tech usually do is not to claim ownership of your data, but require in their ToS that the user gives them a very generous license to the data. That is the legal ground that allows them to do what may be considered shady practices with the data, but that is different from claiming ownership. When you license out your content or data instead of handing over ownership, you too can still use your own content or data (in the legal sense, although it might be technically difficult to extract the data out of the service, but that is another matter), you can license it out to other third parties (if the license was non-exclusive), you keep your moral rights over it (many jurisdictions prohibit waiving moral rights), etc.
So I’d say you don’t lose ownership of the data, but you do completely lose control over how the data is used.
To make it clear, I do agree with the proposed change of wording of the case. When a case is changed like that, does it mean that we have to evaluate every point that uses that case? I suppose so.