I think many teams should manage a single service, which really drastically lowers on call support burden. Unwieldy is a single team (10 or fewer people) supporting a service by themselves, or more than one service by themselves. If at the point you have 16 microservices, that means you should have 16 very distinct areas of technology and business. The monolith to 4 services was an example, and I think you should really be careful each time you carve out any area of business, and the better focus is on focusing on how to scale the monolith further.