The Scrum Master should do this because it is the most effective way to ensure that the Scrum Teams are self-organizing, cross-functional, and collaborative. The Scrum Master can help the Scrum Teams to understand the benefits of working together as one integrated team, rather than as separate component teams. The Scrum Master can also facilitate the communication and coordination among the Scrum Teams, and support them in resolving any dependencies or conflicts that may arise.

References:

Scrum Guide 2020, page 7: “Scrum Teams are cross-functional, meaning the members have all the skills necessary to create value in each Sprint.”

Scrum Guide 2020, page 7: “Scrum Teams are self-managing, meaning they internally decide who does what, when, and how.”

Nexus Guide 2020, page 5: “When multiple Scrum Teams are working together on the same product, there are additional complexities that arise. These complexities can be reduced by having the teams adhere to a common definition of “Done” and a single Product Backlog.”

Scrum is a framework for addressing complex adaptive problems, such as product development, that require empirical process control and frequent inspection and adaptation. Scrum helps to mitigate the risks of:

The timescale of the planned work (A), by delivering potentially releasable increments of value at the end of each Sprint, which is a fixed time-box of one month or less.

The stability and complexity of the technology (B), by allowing the Development Team to self-organize and choose the best way to create a “Done” increment that meets the Definition of Done.

The complexity and unpredictability of the requirements ©, by enabling the Product Owner to manage the Product Backlog, which is an ordered list of what is needed in the product and can change as more is learned about the product, users, market, and technology.

The skills and working relationships of the people on the teams (D), by fostering a culture of collaboration, transparency, and accountability among the Scrum Team members and stakeholders.

References:  : [Scrum Guide], Introduction : [Scrum Guide] , The Sprint : [Scrum Guide], The Development Team : [Scrum Guide] , The Product Backlog : [Scrum Guide], Scrum Values