Instant ship production and continued design development

Would instantly copying warships stop Britain from developing better designs?

The premise allows design work to continue: Britain could rapidly produce Flower-class corvettes and then develop the Castle class.

The proposed objection is that copying ships would discourage original development and eventually become a dead end. In this scenario, Britain can still develop designs normally and then produce them almost instantly. A request for 200 Flower-class corvettes could produce those ships ten days later. Development of the Castle class could continue while the Flowers were already available for escort work.