A large engineering org is almost always horizontal, whereas some narrow problems are unusually deep and/or important and therefore benefit from unusually skill

A large engineering org is almost always horizontal, whereas some narrow problems are unusually deep and/or important and therefore benefit from unusually skilled attention down to the micro level. In some cases you want your three wizards supervising the architecture of 100 people working on 25 products… and sometimes you want them lovingly crafting every line of a framework or other core component that is going to mechanically influence all that work even more than design review ever could.