Why don't the women have to play best of 5. Billie Jean wanted equal pay for equal play. Best of three really allows a hot streak of say an hour to determine the winner. It's not like the can't do it because they are the weaker sex. A women's marathon isn't 60% as long as the men's.
I'm repeating much of what was said above, but you, as a viewer, do not want the women to play in five set matches. The fourth and fifth sets would be played at about the level of a men's 4.5 level player, but only intermittently between injury timeouts. Vegas would begin setting over/unders on the total number of trainer calls per match.