The choices a manager makes are very different from the choices a technologist should be making, and its not about what tools or tech stack you are working with. It is about things like how do I enable my team to deliver, because one thing people love to do is see how they can make excuses for failure to deliver. At the tech level its about how leadership and management makes poor choices, at the leadership level its about how your workers are lazy and unable to perform under such and such a condition. In reality its both parties trying to insulate themselves from failure by having a scapegoat.
Empower your tech teams to do great work, it doesn't require you to be a google or apple, or podunk startup. I have seen empowered teams at 10 man contact shops and 100,000 fortune 100 companies. If you run into a company that tries to tell you something else run away, you will find politics and infighting alongside terrible technology and an inability to deliver
If you let your teams individually choose their tech, they will be empowered to duplicate work, and they won't be able to cross pollinate or provide expertise/support to any team that's picked a tech stack different from theirs.
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
Empower your tech teams to do great work, it doesn't require you to be a google or apple, or podunk startup. I have seen empowered teams at 10 man contact shops and 100,000 fortune 100 companies. If you run into a company that tries to tell you something else run away, you will find politics and infighting alongside terrible technology and an inability to deliver