Why Supermarine had reason to prioritize a Royal Navy fighter

Would a failing Supermarine simply have reverted to Vickers?

Possibly, but likely as a broken-up organization; Royal Navy support had preserved the team and gave Supermarine strong reason to prioritize a future naval fighter.

Supermarine might have reverted to Vickers if it failed, but the company would probably have been broken up rather than preserved as the same design team. Its engineers knew that Royal Navy contracts had sustained the business and helped fund the Schneider Trophy work behind later high-performance aircraft. By contrast, the Air Ministry became enthusiastic only after the Spitfire showed its promise. Supermarine was therefore the firm most likely to work discreetly and intensely on the Royal Navy's desired fighter while control of the Fleet Air Arm was being restored. A long procurement relationship could preserve technical capability and create institutional loyalty beyond an individual contract.