What I've always wondered, is when getting into one of those roles (i.e. Tech Lead) without coding history or expertise, wouldn't you be missing credibility?
Leadership is about managing risk, so that is a hard disagreement from me. Any good leader, especially a tech lead, needs to be able to both define the path and execute the path. If you don't have the skills or background to execute the path, you often have no clue what is involved and aren't of much help.
Even when well versed in a domain and related tech, we get surprised all the time.