I'd like to say that co-ops mimic the labour market in that there is a competitive aspect to the job search.
Students apply for jobs. They have agency, in that they can choose which positions suit their maybe desired career goals, but they do have to compete for those. They're interviewing. Employers are selecting them. In the end, the student decides to accept or decline an offer. With that, student engagement in the job search process certainly does play a role. There are times when students won't complete work terms, but I think most co-op institutions have resources in place to support the students to help ensure success wherever possible.