My company does this in a sense. We build a (mostly) open-source eCommerce platform with almost 100 public repos and a lot more proprietary ones for larger retailers. It's not "microservices", but it's definitely a lot of packages to manage, and we have frequently had trouble keeping them all organized and in sync with the latest changes to the core platform. The core platform is designed internally with a modular, domain-driven architecture, and the applications made with the platforms are monoliths, but the features of the platform are distributed amongst a couple hundred RubyGems. It's a lot to keep track of, but it's still a great compromise between a modular, plug-and-play architecture, and a monolithic application with all those features installed at once (which would be really hard to maintain). We're looking for ways to reduce our workload in that sense, because our team is rather small (about 6 people) and as I was saying, it's a little difficult to manage all those repos. So we've been thinking about keeping the modular architecture but keeping everything in a monorepo, so it's easier to release new versions and figure out what's changed (or what needs to change).