> a massive team is following a rigid SDLC including code reviews for best practices

Regardless of how thoroughly a system is planned in advance, programmers are not automatons who mindlessly fill in the last few blanks. They must make choices about the code they write, and that is absolutely a part of the overall design. If that code fails a code review, well, then it gets rewritten, but that's ancillary to my point: programming is design (albeit at a lower level than the overall system design).