How was this considered a flop?

I always read how this film, along with Two of a Kind and Perfect, killed Travolta's career pre-Pulp Fiction and that this film was a bust. I can see that with Two of a Kind and Perfect since they were indeed bad flops. However, Staying Alive grossed over $64 million and was in the top ten films of the year. It even beat the gross of Urban Cowboy, which is widely considered a blockbuster and Travolta's last huge "hit" in his initial heyday. Why does this film have that stigma when obviously it grossed quite a bit of money, especially in 1983 dollars? Was it because the critics trashed the film and the fact that it had Stallone's name attached to it? Was it because they were comparing it to Saturday Night Fever and it didn't meet up to that's film expectations, critically and financially? Or was it that Two of a Kind's failure killed the success this film built up? Either way, I think it is still good popcorn entertainment and Travolta was in top form physically.