[Guyver Spawn]

I think people like the idea of a solo hero than a team of heroes. Not to mention the tone for Kamen Rider will feel a bit more serious compare to Super Sentai. I always find the older Rider shows more violent than the older Sentai shows in my opinion.

I also hear Kamen Rider does tend to sell more toys compare to Super Sentai. I think kids from 5-12 find the Kamen Riders to look cooler than the Rangers because Kamen Riders have more detail to them and will have armor on them while the Super Sentai rangers are pretty simple and plane looking.