"The kids willing to give up their summers for education have a different level of drive than the ones that attend the rest of the year."
Not really, if anything it takes less drive. It's vastly easier to take classes over the summer (when classes are usually easier), and then do your internships in fall or spring when there's no competition. The only reason not everyone does this is that it wouldn't be financially viable.
Since when can you not apply financial aid to summer classes? When I was in college (10 years ago), the rule was 2 semesters/year.
Summer usually wasn't viable because class selection is limited. For example, Quantum Mechanics 1 is fall semester, Quantum Mechanics 2 is spring semester, and you need both to graduate.
Not really, if anything it takes less drive. It's vastly easier to take classes over the summer (when classes are usually easier), and then do your internships in fall or spring when there's no competition. The only reason not everyone does this is that it wouldn't be financially viable.