Corporate doesn't care at all about privacy. It's why the run outlook and windows and let Microsoft scoop up all of their company secrets. It's why they hand every scrap of data they have on their customers to salesforce and surrender their data to Atlassian and use Confluence and JIRA over countless alternatives.
All companies care about is that when data breaches happen publicly they can point the finger at someone else.
And with things like Fable mandating data retention at Anthropic it makes things business records which US Federal Administrations have a history of obtaining without warrants and under mandatory gag orders like national security letters. They generally won't issue those directly to law firms (because they can and will fight), but IT companies generally comply quietly and have government contracts to think about.
If however, our internal IT group didn't read the manual correctly and set up our cloud service access parameters incorrectly so that anyone who was trying to probe our defenses could access the formula, Jim from IT is looking for a new job.
See the difference?
You'd never hear about if it the cloud service was taking your corporate data and using it for countless other things though. Insider trading, selling leads to your competitors, pushing ads to your clients/customers with offers of their own products, using trends in what your company and others are doing to guide development of their own products and services. Done carefully, you'd never be able to trace any of it back to them and it'd take a whistleblower for you to find out it happened in the first place.
I don't imagine any cloud service that has massive amounts of data which could easily make them a ton of money is just ignoring it.
I doubt they want to risk their reputation, trust and agreements to make money in the ways you describe.
All it takes is one incident, and all your company's internal data will start showing up in public users' chats. You can rely on a contract to prevent this, or you can guarantee it by using a locally hosted model you fully control.
When combined with the cost savings and good enough performance mentioned in the article, this can become a huge selling point.