I think most of google sucesses outside search were done like that without the CEO having knowledge.
That said, probably more often than not, there’s an actual value in it.
For example: Android was a completely diferent tech stack from google.
Maps: bought
Youtube: bought
Android: bought
What else?
They are still more or less separate software stacks. (Disclaimer: This knowledge is outdated by about 2 years, but a significant change is unlikely. )