I think a major issue is the lack of motivation a superstar woman player will generally have to reach higher in her game.
The modern women's game has known two dominating presences, Jean Balukas, who won practically every women's event she played in, and Allison Fisher, who has won roughly half of the WPBA events she has entered over thirteen full seasons played. I saw both play very often in their primes, but can only speculate as to how each thought out how to manage their development as players.
OK, put yourself in the shoes of Jean Balukas in the early 1980's. You're the best woman player ever (or at least on a par with the great Ruth McGuiness), winning every women's event in sight. You already have the Brunswick sponsorship deal, the most lucrative available of your time for a woman player. You can continue winning most women's events even if you aren't a practice room devotee, because you're that much better than your contemporaries. You are good enough to compete with, but probably not good enough to finish high in men's events with any regularity, unless you are willing to become a practice room workaholic, and even if you do, your income probably won't grow appreciably. Few presented with a similar situation would make the enormous effort required to bring their game to the next level.
OK, now you are Allison Fisher in the late 1990's. You are the best woman player in the world, bar none, and you have the lucrative Cuetec deal, meaning you have a good income from pool. The financial rewards available to you if you make the enormous sacrifices to bring your game to the higest possible level are fairly modest.
As I've noted, this is pure speculation as to how Jean and Allison approached the management of their games, but what is clear to me is that the two greatest women players ever each reached a point in their games where incremental development would require huge sacrifices and would not be especially remunerative. The top women are armed and dangerous, as they showed in Las Vegas last week, but until the undeniable superstars of women's pool have more financial incentive to raise their games to the highest possible level, I must wonder whether we should expect the top women to reach the level of the most elite men.
That's my slant on it.