The product is mature enough to warrant all of those things, and when new members of the team are on-boarded, time is certainly carved out for code orientation.

The product is mature enough to warrant all of those things, and when new members of the team are on-boarded, time is certainly carved out for code orientation. However, being forced to work on a story from beginning to end with a team member who knows how to pair well and knows the code base well is even more valuable in the end. Pairing is absolutely the best way to share knowledge, as it is necessary for the pair to be successful.