Tens to low hundreds possibly, but micro services can make things much worse as you scale to thousands of developers. The ultimate limit of any design is how much any one person can understand both from both a complexity standpoint and a rate off change standpoint. It’s the same issue that pushed people from goto > functions > libraries > ... Eventually you need another layer of abstraction.

For very large companies doing mergers etc things are always going to be in flux in ways that the startup world tends to ignore.