It all depends. If you are using existing IP, then the design part might be shorter. Conversely if you are using a proven process from a contact fab, you just n

It all depends. If you are using existing IP, then the design part might be shorter. Conversely if you are using a proven process from a contact fab, you just need to follow their design rules and they will do all the manufacturing work for you. But companies like Intel, AMD, Nvidia push the boundaries of everything. They have separate teams working in parallel on different aspects (design, fab, etc) and generations of products.