As somebody who is completely puzzled why you could think that the cloud is a terrible bet for many companies - are these companies allowing their employees to use Google Search or other parts of the internet or do they have to look up things in paper books in the corporate library?
Let’s not pretend Google search is what people mean when they say “cloud.” It’s about running internal processes on external systems.
As to the risks, many companies live and die by their internal secrets. These range from a private keys, customer lists, trading strategies, and similar trade secrets to actual serious R&D efforts.
Sometimes the damage is obvious such as crypto exchanges suddenly finding themselves broke, but corporate espionage can also be kept quite. Losing major government bids because a competitor read some internal memo’s is a serious risk and you may never know.
It’s much harder to reconstruct actionable intelligence from a huge stream of people using Google search even if they’re using it to preform sensitive calculations.
While theoretically possible for something bad to happen, short phrases are much less likely to have actionable/sensitive info in them than the full document corpus of a company.