I grew up knowing more Janet than Madonna, but it doesn't mean Madonna is a flop. People underestimate Janet because of Nipple Gate, but she dominated in the 90s. She may not have been the international slayer like Michael or Madonna, but she was still huge. Janet just failed to keep up with times (her last albums were dated) or have universal appeal..which pretty much helped people write her off in recent memory.
Janet Jackson is one of the highest selling female artists of all time with a memorable video discography at her disposal. Some of you may not know her videos, but pop culture does. I'm pretty sure your fave does too