So, no choice of language and no choice of the libraries used. What’s “everything else” exactly? Sounds like missing out on the more interesting parts of a micro service architecture.
1. In the 10-5000 employee range: tech giants are a different beast when it comes to team accountability.
In the microservices organizations I've seen, this isn't true. The other service teams provide an API and, like any other SaaS you use, you do not need to be able to read the implementation. You would only work on that code if you switch service teams.