I hear that American female basketball players make more money playing overseas than in the WNBA, some superstars quite a bit more, but how much is more and is it only Americans who command high salaries? The number of pro women teams outside the U.S. is extremely high. Are audiences that large or are there subsidies? I have been told that because there are fewer super athletes (which I question) that the European game is more cerebral which is why someone like Anna Makurat with her court IQ is in high demand in Poland.
Answering some of the parts of the question that have not been answered...
It is not just Americans. In fact, in demand Europeans make way more than everyone other than the best Americans. That is why a lot of players who are outside of Team USA consideration choose to take on European citizenship, playing for the national team a bit and increasing their salaries for their club careers. People who have not taken up European citizenship, but qualify to should definitely be thinking about getting it as young as possible as the rules changed to allow someone like Sabrina Ionescu to count as a European even if she represents the United States. Very few leagues require any kind of public disclosure so official figures are hard to find and it is occasionally hard to tell whether figures are pre or post local income tax since most people quote salary post-tax in general use. The French league has some more information than most and it generally looks like all of their teams have a higher payroll than WNBA teams. EuroLeague champions Ekaterinburg are estimated to have a post-tax player payroll of around 10 to 12 million dollars, though there are some suggestions that it may be more like 15 million dollars. Runners up Avenida reportedly had a post-tax payroll of around 1.3 million dollars. Semifinalists Fenerbahce announced that this season they plan to cut their payroll to around 1.5 million dollars post-tax.
Sometimes teams and players have salary disputes and contract details become public here:
Basketball Arbitral Tribunal (BAT) - FIBA.basketball
Ketia Swanier and Tina Charles were recently involved in disputes.
The athletic baseline for teams in general is not as high in Europe as in the WNBA. That means that players can be effective players even if they are missing one or two key attributes so you have athletic players with no skills, skilled players with no athleticism, players who would seem too short to play their listed position, players whose conditioning only lets them play limited minutes effectively, and everything in between. The ability to play zone and the physicality allowed does tend to negate fast or athletic players who do not have the skill to make defenses pay.
Makurat is in high demand in Poland because she is Polish and the league is trying to increase the amount of Polish players getting minutes. Even then, the long term goal for her is to prove that she can be a contributing level player on a higher level team and move abroad unless more money comes back to the league, which was hit hard relative to some other countries that were traditionally about the same level. In some leagues, the best players who count domestically are in much higher demand then Americans because below the top level, Americans are fairly interchangeable and there are a lot of them who are willing to take less to try to make a name for themselves in professional basketball. A lot of Americans who qualify for Israeli citizenship take it and play there because the salaries are pretty good, even for players who did not play DI here.
There are some different situations going on in Asia and we will see how things change there as some leagues ran without foreigners this past season. In China, most local players are not paid much and generally live in less great conditions while the lone foreign player lives in a hotel and makes a relative ton of money. In South Korea, the last time they had foreigners, they were all paid around $125,000 after tax depending on how far their team went and accommodations are pretty nice with one foreigner per team. Their fellow starters all make more with the top Koreans making around $400,000 post tax. Kim Roberson, who played at Indiana, is part-Korean so she is able to play as a local there and as a result is one of the highest paid American women playing basketball even though she would be far away from WNBA consideration. The money there is so good that former Rutgers player Chelsey Lee was famously caught in a scandal claiming to have one Korean grandparent.
Audiences are not large and pretty much all ticket prices would seem very low to us in the United States. Some of the costs associated with teams that have to be dealt with here are less of an issue there. There are no college teams to compete with so coaches get paid far less relative to players. Since tickets are cheap, there does not need to be an entire business side of the operation trying to provide customer service or marketing. Travel is generally cheaper and costs for your home facility are cheaper or handled by the local government. Also, in most countries, then men's league players make significantly more than the women's league players as well so there is generally no special appreciation or valuation of women's basketball overseas that is not present here.