The disparity within AWS is the result of common inevitability that arises with managing technology built on over a decade of scaffolding. For sure there is a central planner within the company trying his best to put everything together into a cohesive whole. Technical debt is the most common name for this issue.

An "Architect" can't solve this problem anymore than an "Engineer" can fix the problem of technical debt because neither person can see the future. It's like pointing at everything wrong with a piece of technology and saying an "Architect" could've fixed that in hindsight.

"Architects" are not the solution to technical design and technical debt.

An engineering manager can place all engineers in a room and ask them to come up with an "architecture" that is the same if not better than anything a single "Architect" can come up with, and this "Architecture" will never solve the problem of technical debt for the same reason why we can't predict stock prices.