She did not win a single WTA tournament, leave alone a grand slam tournament.
She was a very good doubles player, reaching #1 with Martina Hingis. She won two grand slam doubles. Plus she is smoking hot and gave women’s tennis some much needed sex appeal. She was good for the game.
Doesn't matter. Pro sports is primarily entertainment. Viability is dependent upon people watching. People watched her. It saved women's pro tennis from the fate of the WNBA.
She did not win a single WTA tournament, leave alone a grand slam tournament.
If that is your measurment of success you are missing the point (and may possibly have contracted "teh ghey"). FWIW, Marilyn Monroe never won an Oscar either.
When she was in her prime, any decent men's college player would have beat Martina Navratilova love & love.