What science is being done with ISS?
To start off, technologies for power generation and life support in space are being developed, along with the international cooperation mechanisms that will be essential for all future manned space flight and space development.
As for the material, biological (medical), and chemical processes that are being worked on in the unique low gravity environment of space, you are correct that those technologies are not getting to US industries.
The reason for that is relatively straightforward, and that is another problem the next NASA administrator will work.