really is that simple. In many countries men's soccer is the number one most popular sport. And in most countries where it isn't #1, it's second. And it has been that way for decades. In the US, soccer isn't the most popular. It isn't even in the top 3. There's an argument it's top 5 and climbing due, in part, to immigrants.
In short, other countries care a lot more about men's soccer than the US and a lot less about women's soccer.