Why isn't the ‘Designated Player Rule’ rule, which allows the men's soccer league teams to sign star players, also been applied in the NWSL just as it is in the MLS? Thus, the women's clubs are prevented from paying more money to star players in order to attract them.
Because of the difference between the leagues.
- MLS is a second-tier league. The big names of men's football play in Europe, or very occasionally in South America. The only way that MLS can attract one of the big names of men's football is by paying them wages higher than they could earn in Europe - and those wages would absolutely destroy the MLS salary cap. For example, the average salary for a Premier League player is around £3m per annum per player; that would be about 90% of the MLS salary cap per team of $4.2 million.
- NWSL is probably the top women's league in the world. They have no need to overpay to attract the top players in the world; it probably helps that the US is the top women's team in the world, but definitely not in the men's game.