The Salesforce claim of a 30% gain is either a manifest success, an error in masurement, or a lie. I really have no way to tell.
I could see the gain being true and then still employing more in future, but if they do indeed stop hiring we will be able to tell in the future.
The future is not now.
Most of this stuff is very, very transparently a lie.
There are real products and good use cases, and then there is this massive hype that can be seen also here on HN. Carefully crafted PR campaigns focusing exactly on sites like this one. Also doesn't seem sustainable cost-wise long term, most companies apart from startups will have hard time accepting paying even 10% of junior salary for such service. Maybe this will change but I doubt so.
Basically the industry is pretending like these tools are a guaranteed win and planning accordingly.
Personal anecdotal, IBM has never been the same and will never recover