You can't say this without sparking some sort of outrage these days, but if people can be serious for a minute, the WNBA is a slower, less athletic, weaker, and shorter version of mediocre high school boys basketball. It's not good basketball. It's just not, and Clark's popularity is coming mostly from the fact that she has a once in a generation all-around skill set that even current all star level players in the WNBA just don't have.
I'm not going to hate on the WNBA or anybody that chooses to watch it, but there's a painfully obvious reason that it's in the financial hole that it is, and people can see it any time they turn on a game that doesn't involve CC.