If the teams are working on similar problems, and if the teams actually work together they will stabilize on a singular stack. There will be cases where work wi

If the teams are working on similar problems, and if the teams actually work together they will stabilize on a singular stack. There will be cases where work will be duplicated, and there will be cases where tech components need to be refactored because the stack has changed, but you will end up with a very well known and understood set of tech primitives that your services are built out of. There are lots of reasons why you may never hit that state of everyone self selecting the same or a very similar stack, but they are never technical and they always indicate a team structure problem that is going to cost you way more if you don't deal with it then the amount of duplicated work you might encounter