I don't think that Evert played second fiddle to Martina for most of her career. People just tend to focus on Martina's 13 match winning streak over Chris and voilà - that's the Martina/Chris rivalry in a nutshell for them. But there were periods when Chris dominated Martina, periods when Martina dominated Chris and periods when it was more or less even.
I agree with this. But I guess this is sort of also my point. In the same way that people focus on Martina beating Chris 13 times in a row, Martina winning 6 Grand Slam titles in 83-84 (similar to Seles' 91-92), and Martina leading her Grand Slam H2H against Chris 14-8 (10-4 in finals, according to wikipedia), people also tend to forget the points you make that Steffi remained competitive against Monica even during Seles' dominance of the tour.
You forgot the part where Seles is 4 1/2 years younger than Graf. Graf had a massive head start in everything and in 1989 accumulated 3 wins against a 15-year-old playing her first full year on the pro tour.
Well, while chris Evert and Martina are separated by only two years and they started playing professionally at around the same time, Chris won 7 Grand Slam titles before Martina won her first. After 1984, I reckon most people must have thought that that Martina would just keep on winning because by then she seemed to have the upper hand over Evert and everyone else. But somehow Evert, at the age of 31 in 1984, still managed to win over Martina again after that and even won 3 more Grand Slam events from 1984 onwards.
I'm not saying it's an exact comparison. All I'm saying is that while one person may have shown absolute dominance over another for a certain period of time doesn't mean it will continue in that same way throughout the rest of their careers.
In any case, I'd like to highlight what Chrissie-fan said:
But when some bloggers and even people like Pam Shriver almost casually start taking away slams from Graf and assume that Seles would have won everything under the sun, that's not fair to Graf either. To be honest, there is no right answer to the question of how the Graf/Seles rivalry would have played itself out over the years. We just don't know. All we know for sure is that we as tennis fans were robbed of one of the great rivalries in history.
I agree with this. And as I've said, even if Seles ended up with 20 or more titles and Graf ended up with 15, Graf would still have been an all-time great. I just wish these bloggers, writers, and tennis players at least acknowledge this. The way things are being written now, it's almost like Graf has no place among the legends of tennis.