My observation: No it will not immediately become a major US sport, But:
The reason that these other sports are strong is because we/everyone grew up playing them. Forty years ago,(more or less)nobody played soccer in the US.
Probably 25 or so years ago soccer started being played by kidson a local level, and it has grown in a large way. A lot of schools play it, and it continues to bea growing sport in the US.
So effectively, there is a generation that has grown up with soccer, and when they decide to support it, it's going to happen.
Now winning the WC would be a major boost.