> Service A could be written in Java, service B could be written in Go, service C could be written in Whitespace, if you’re brave enough.

I've always found this to be such a huge strawman. I've yet to encounter an organization that uses a variety of technologies. Usually it's one of the top most popular, sometimes two, rarely three different languages. Devs migrate between teams, hiring is done to match the skills already onboard. Coding styles (even if they differ slightly between teams) usually follow corp "best practices"

Even if it's a multitude of services, the culture of the codebase is usually very monolithic.