How deep should a Network Architect go into knowing a specific product or technology

In my view as network architect you need to understand the principles and you have to be able to create high level designs/architectures that will map business requirements to network functions. Then the design is refined by an engineer.

These days the network devices are quite complex they are capable of working with lots of technologies, some open standard some vendor specific, each vendor implementation of the above coming with its own limitations or specifics.

How deep does an architect need to know vendor products in order to be able to do proper high level designs. Let's not forget that most of the cases the companies become vendor shops and they stick with one vendor for most of the technologies they use (Ex: Juniper, Arista, HP etc). Do you need to know CLI and hardware specifics? Do you need to know about capacity limitations? What would you focus your learning on if you would hold such a position in your company?