Money played a big part in my kids graduating in 4 yrs/8 semesters.
For one, and engineer, her scholarships lasted for 8 consecutive semesters only. If she’d gone an extra semester, it would have cost her about $30k. Her athletic scholarship and her state funding were gone. She might have been able to get a new merit scholarship but that wasn’t likely. So she plowed through and did a very traditional 8 semesters in a row, no summer programs. Many of her friends did co-ops and internships and I think the school found a way to extend the 8 semester rule if the student was away on co-op, but my daughter’s athletic scholarship made that harder to organize so she just went for 8 straight semesters.
Her sister took one semester off to do a Disney college program. She also did a semester abroad that only allowed 12 credits. She changed her major 3 times (!), so to graduate in 8 semesters she took classes one summer. She wouldn’t have had to, but it would have been two really packed semesters for her last two. The summer credits gave her some breathing room. She also had a scholarship for 8 semesters only.
Some kids, even those with high financial need, just don’t have the luxury to stretch out graduation. Mine were limited by scholarship and grant terms set by the schools or the state.