A few words on why hierarchy is in fact the enemy, and how a network of teams is a simple answer to a complex problem. Most of my beef with hierarchy is around learning: who gets to learn what and what lessons are prioritized by the org.
Hierarchy enriches leadership, but not how you think
Here's a normal-looking team, reporting to a senior leader. Let's imagine that these seven people are running seven different projects (with teams supporting them, or running them solo). They're reporting progress, insights, getting guidance from the leader, getting unblocked, etc., on some sort of cadence. Let's say that happens weekly.
From this group of people alone – not including any other pieces of business they're running with peers or working groups outside their team – the leader has seven sources of curated information; if they can keep track of all of the moving parts, they have an opportunity to get very, very smart about a wide-ranging set of topics.