Same line of thinking, just different conclusions.
I feel terrible for anyone trying to run a company with open-source style independent repos. On a popular github project, you have MANY potential contributors that will tell you if a PR, or a release candidate break API compatibility, etc. There are thousands of hours in open source dedicated to fixing integration issues due to the (unavoidable) poly-repo situation.
Monorepos in companies are relatively simple. You need to dedicate some effort in your CI and CD infrastructure, but you'll win magnitudes by avoiding integration issues. Enough tooling is out there already to make it easy on you.
Monorepos' biggest problem in an org is the funding, as integration topics are often deprioritized by management, and "we spend 10k per year on monorepo engineering" for some reason is a tough sell for orgs, who seem to prefer to "spend 5k for each of the 5 teams so that they maintain their own CD ways and struggle integrating which incurrs another 20k that just is not explicitly labeled as such".
Developer team dynamics also play a role. I have observed the pattern now multiple times (N=3):
* Developers have a monolithic repo, that has accumulated a few odd corners over time.
* The feeling builds up that this monolithic repo needs to be modularized.
* It is split up into libraries (or microservices), this is kind of painful, but feels liberating at first (now finally John does not break my builds anymore)
* Folks realize: John doesn't break my builds anymore, but now I need to wait for integration on the test system to learn if he broke my code, and sometimes I only learn it in production.
* people start posting blog posts on monorepos
That pattern takes 2-3 years to play out, but I have seen it on every job I worked.