Harmony between Multiple Management Theories

One of the promises and a great point that theories of
1. JIT
2. Critical Chain
3. Agile Practices
4. Earned Value Management
5. Systems Thinking
propose is to streamline operations and management across every key business functions. And the target of reducing waste is multifold:.

1. Keep near to zero inventories
2. Identify the bottleneck (Constraint) and work to eliminate the constraint. Never let Inertia be the constraint
3. Make Velocity the primary driver on projects
4. Plan closer to realities and meet forecast due dates and costs every time
5. Ensure to look at whole than to address it in parts (more appropriately think long term than to spoil it for short term gains)

What each of the theories explain is in harmony with other theories. It is the context and culture that defines the importance of a theory over other that determines the extent of practice within an organization and industry. Manufacturing and automotive industries is
where JIT had its origins. Book "Goal" where ToC parable was made known
to everyone is set in a plant. IT and software industries do not need warehouse inventories as they rely on human capital. Hence agile practices are more common. In RnD organizations, science and infrastructure industries that need heavy investments and need long term management for results and control on cost escalations, EVM is more appealing. 
In my experience at team, product, project and service management, I realized that bringing in the understanding from each of these theories and crafting your operations model is a great way to deliver exceptional customer satisfaction, team achievements and a sustainable long term sustenance of business, teams and clients than a short get-together for climbing up professional ladder.