Ask HN: Using manyrepo and happy with it?

I'm looking for examples of big companies using many git repos which are happy with it.

I have colleagues who want to restructure our repos towards a monorepo. The hope is that it solves our integration problems. The argument is that Google, Facebook, etc are better software companies than we are and we should copy from them.

I believe a monorepo will not solve integration problems. I fear it might only make them worse because our automation (Jenkins etc) is not good enough yet.

In the enterprise the argument of "others are using it" is a strong one. It is similar to the "nobody gets fire for buying IBM". Is there are good counter argument? Are there big companies which use many git repositories and like it that way? How do they work at Amazon, Microsoft, IBM, Oracle, SAP, VMWare, Apple?