The niche Next dominated before they started chasing the RSC dragon was scaling SPAs with complex frontend state.

React Query and atom based state management offered nice alternatives to Redux/Context hell, and Next could have just hung up major architectural refactors for QoL updates.

They want to dominate the headless Shopify/CMS niche, but that doesn't have to mean dragging Next.js along for the ride. It was a business/branding decision, not one that actually benefits most users of what they had already had.