[Guyver Spawn]

Power Rangers is a way bigger brand name compare to Pacific Rim. Pacific Rim was a original film that was inspire by classic 70's mecha anime while PR has a lot of nostalgia value to it like Uchibabro77 said. Not to mention the PR movie will likely do well in Asian countries like China and South Korea (PR is a popular brand name over there as well). So at least it will likely do well in overseas even if the movie flops in the US.