The service academies which are generally known for being selective even if their overall programs cannot be compared apples-to-apples with similarly ranked civilian colleges, represent an interesting example of the OP’s question. By mission and design, the SAs value brains and brawn somewhat equally, so their incoming classes comprise a broad range of scholastic aptitude. Like civilian colleges, the SAs maintain an academic bar that all incoming appointees must hurdle, no exceptions even for athletes, but only one-third of any incoming class is selected for outstanding academic chops. The remaining 2/3 are chosen for equally shiny traits but fall further down on the academic scale. Obviously, some enter at the bottom of that scale even though they pass the admissions standard like those the OP is questioning.
Freshman choose their majors at the end of freshman year and guidance (“nudging?”) is both by interest and aptitude as shown by first-year performance. Navy, for instance, is purely an engineering program, so “easier” may be relative. Army offers a wider curriculum and, certainly, some choose paths that help ensure higher GPAs as GPA is one component of class rank that affects which branches a cadet has reasonable access to. The academies do everything in their power to support their students through to graduation with small class sizes, easy access to the brain trust, and freely available peer and faculty tutoring available 24x7, but they do expect students to know when they need help and to seek it out. The difference at the SAs, though, is that each student is a member of a corps glued together by an ethic that no brother is left behind, even on the academic battlefield. Our son is a math peer tutor and spent many hours freshman year doing his damnedest to ensure no one in his company failed a math class though some did. Even with all these support structures, some don’t make it, and the sifting is transparent and harsh: Fail a class, any class, twice and you’re out. Cut and dried. But it’s not always those entering at the bottom of the class who struggle. One of our son’s freshman roommates was valedictorian of his high school. He was separated for academics at the end of freshman year, but he was not an outlier. Some at the upper end of the incoming academic scale just don’t seem to be able to admit they need help until it’s too late. Some lower on the academic scale are used to getting help and don’t attach any stigma to reaching out to those more advanced; they will make fine officers. By graduation, they’ve all caught up in the sense that they have endured the rigor and earned their commissions and the right to be called “sir.” At West Point, each member of the graduating class donates a dollar to the kitty presented to the “goat,” the lowest ranked cadet on the graduating totem pole, and that cadet is celebrated for finishing the race.
Because the SAs are Federally mandated to produce and maintain a certain number of officers per branch, they go to extreme lengths to support their students toward that goal, but civilian colleges are evaluated by graduation rates, too, so they have an interest in helping their students earn their diplomas. I would say that ALL students, not just those entering toward the bottom of the academic scale, should know which supports are offered by their colleges and how to take advantage of them but, more importantly, understand when to take advantage of them, and that’s the trickier part, especially for freshman who may have been used to extra credit, test corrections, curves, lowest-score-dropped or other grade-enhancing devices in high school that most likely aren’t available to bail them out in college. It is important for all students to understand that asking for help as soon as it’s needed is a marker of strength, not weakness, and it’s our job as parents to send this message sooner rather than later.