Most have to go back. There is only a limited number of students who can stay through programs like H1-B or having a company go through the paperwork of sponsorship.
The Chinese here on PDF keeping talking about how a higher percentage of students are going back to China but most of it is due to simple math. You send more students over but the available slots are limited...well the more that have to go back.
As if all 289,000 students would simply be allowed to stay in the US indefinitely. Of course more of them are going back compared to 25 years ago when that number was probably only 20,000 and most could stay. So of course 25 years ago the percentage staying was higher than it is today due to simple math not by a change in preference.