Not OP, but because it often slows down development since different teams keep re-implementing similar ideas or have strong requirements to allow using their in

Not OP, but because it often slows down development since different teams keep re-implementing similar ideas or have strong requirements to allow using their infrastructure. There are always trade-offs to consider, silo-ing projects can be critical to some core infrastructure projects and security libraries, can be very useful for other control plane projects, but can also actively hinder innovation in other cases. That's a wordy way of saying it's not always the most efficient use of resources.