First off, the 1R loss which everyone claims is why she's not #1, isn't the sole reason why she isn't #1. Serena could have had a *respectable run* of anything from a QF to a WIN, and still not be #1, according to Boiled Egg's updated rankings (though anything but a slam win these days is mocked by the haters. Tards like Dsanders mock her RU result at the USO last year even though it was just mere months after a pulmonary embolism, whereas it took his fave years to get back to a slam final
As far as why she ISN'T #1, I think we all know the answer. Serena doesn't have any Fall points, her injury in Australia prevented her from going deep, and Vika/Maria have done well in all the tournaments Serena hasn't played and minimized the point differential earned in the ones they played together. No, Serena did not play a completely full schedule but she did more than she usually does.
I'm not going to bash her scheduling decisions just because she's not supporting the tour at a couple additional low-rent events a year in the fall (which is very irrelevant in the grand scheme of things). Her schedule management is a BIG reason why she's still in the game and in winning form. Y'all will be so lucky for your fave to have this kind of longevity. I hope for your sakes it does cuz I have grown up watching Serena from a pre-teen all the way into my 20's, and it's been a pleasure. It's just not realistic to play the tour at full schedule, full speed, for year after year and expect to last long at a high level. Before Serena earned her dues as a GOAT, she was out there playing a full schedule like Vika has this year and winning (and I'm not bashing Vika doing that, she's young and fresh, so she should make the most of it).
Serena has been the best player this year from her achievements (most titles, most slams, best winning percentage, etc.) as will be reflected by a likely POY award. However, I will agree that Vika has been the most consistent player across 12 months, and got over the Slam-virgin hump after years of being stopped and proceeded to have a historic start to the year. There also is really no gaps in results this year. She is the most consistent player of the year and that is what the #1 ranking is.