You have to learn to push the envelope in order to continue to progress in strength and ability.
Part of that is being sure your equipment is top notch and in good condition. Another is riding outside the comfort zone. Even more is nutrition while riding. High end bikes run better/farther. Riding up hills will make you stronger. I'm just starting on the nutrition thing and already I have seen some gains I thought were impossible. Keep at it and you will also see improvement.