What is the primary reason the manufacturer cannot transfer venue for the products liability claim?

The primary reason the manufacturer cannot transfer venue for the products liability claim lies in the understanding of how venue and applicable law function in such cases. When a case is filed in a federal court located in a specific state, the substantive law of that state generally applies to the case, regardless of whether the venue is transferred. This principle is particularly significant in products liability cases, where the governing law often directly affects the outcome of the litigation.

In the context of this question, the assertion that State A’s products liability laws will apply upon transfer highlights that even if a change in venue occurs, the substantive legal standards applicable to the case remain rooted in the laws of State A. Therefore, the manufacturer cannot effectively argue that a transfer of venue would somehow eliminate or preclude the application of State A's laws, which may be more favorable to the claimant.

This understanding emphasizes the importance of jurisdictional and venue considerations without causing unnecessary disruption to the established legal standards relevant to the case. Thus, the manufacturer’s inability to transfer venue based solely on the desire to change the governing law is a recognition of the stability and consistency needed in products liability litigation.