Great Post! But don't expect a GraFan Troll to grasp this point!
TennisForum.com might have over 50,000 members worldwide, but half of them are your multiple accounts.
Noting that Martina Navratilova's birthday is October 18, 1956 and that the U.S. Open finishes in early September, let us take a look at her early career USO results:
1973 (64 draw) lost in 1st round to Veronica Burton
1974 (64 draw) lost in R16 to Julie Heldman
1975 (64 draw) lost in SF to Chris Evert
1976 (96 draw) lost in 1st round to Janet Newberry
1977 (96 draw) lost in SF to Wendy Turnbull
1978 (96 draw) lost in SF to Pam Shriver
1979 (96 draw) lost in SF to Tracy Austin
1980 (96 draw) lost in R16 to Hana Mandlikova
1981 (128 draw) lost in FR to Tracy Austin
1982 (128 draw) lost in QF to Pam Shriver
1983 (128 draw) Champion
It's remarkable that it took her until she was almost 27 years old and in her 11th appearance in the main draw before she finally broke through. Also remarkable was that she wasn't even losing to established all-time great players, but instead to age peers or next wave or "Who?" players. Evert in 1975 was on her way to winning only her first USO, and had only three Slam singles titles to her credit; at that stage, she was no Doris Hart. Navratilova herself, at the time of her 25th birthday, only had two Slam singles titles with a third to come a few months later -- not exactly record-rewriting results. Hana Mandlikova had won four Slam singles titles by the time she was 25.
But then different players mature physically, emotionally, and gamewise at different rates. As do they wear and/or burn out at different rates. As do some find that their walkabout years extend their productive careers while others prefer to put in a solid 10 years and retire while still youngish. Some want to play until they can't get into prequalifying for a $10K event. There is no "one way" to do things in tennis.