Performance tuning in SQL Server can indeed help reduce licensing costs, and it can achieve this in several ways. Here's how:

1. Reducing Core Counts: SQL Server's licensing model is typically based on the number of cores (for the "Per Core" model) or users (for the "Server + CAL" model). For the "Per Core" model, which is often used in larger enterprises, you pay based on the number of cores in the server. If performance tuning can help your queries and other operations run more efficiently, you may be able to achieve the same performance with fewer cores, thus reducing your licensing costs.

2. Maximizing Use of Existing Licenses: Before purchasing additional SQL Server licenses for better performance or more capacity, performance tuning can help ensure you're making the most of your existing licenses. By optimizing your SQL Server setup, you can often handle more data and serve more users without the need for additional licenses.

3. Consolidation: Performance tuning might reveal opportunities to consolidate databases or instances on fewer servers, which could reduce the number of required licenses.

4. Cloud Deployments: If you're running SQL Server in a cloud environment, performance tuning can help reduce resource consumption (CPU, I/O, etc.), which could lead to savings on your cloud service bills. While not a direct saving on licensing, this still helps reduce the total cost of running SQL Server.

5. Avoiding Over-Provisioning: Businesses sometimes over-provision resources out of an abundance of caution. Performance tuning can provide more accurate metrics and forecasts, allowing for more precise provisioning that meets but doesn't significantly exceed the organization's needs, thus saving on licensing costs.

Remember, while performance tuning can help reduce licensing costs, the primary goal should always be to improve performance and ensure the database's smooth operation. Any cost savings are a bonus on top of these benefits.