The Hurricane was at or near the end of its development, and would have been ineffective against later German aircraft, regardless of the numbers put up. Britain would have fairly quickly run out of pilots.
The Hurricane was 2/3 of the BoB force. The RAF would still win with 3/3 Hurricances but the fight would be harder. The Spitfire was more expensive to produce and maintain too so there would be larger numbers of replacements.
A possible course with no Spitfire would be to produce the P51 under licence with the Merlin engine meaning earlier escorted missions. The Spitfire was a pure interceptor not ideal for offensive operations.
The Spitfire was a great plane but something would have filled its place, unlike the Mosquito which was truly exceptional.