This is a great point. Historically, both USMA and USNA will separate 200-300 cadets/mids for various reasons (academics, honor, fit, health, etc.) before graduation. They count on that. No one commissions from a service academy without fully understanding what they’ve signed up for. To that end, the academies give cadets/mids two full years to walk away with no service or financial obligation. It’s not until you raise your hand and take the oath of affirmation the first day of your junior year that you incur an obligation to the nation to complete your service. If you separate even a day after taking the oath, you also incur a serious financial obligation.
This is an important point as well. Though the academies are degree-conferring institutions, your major/degree is mostly for your benefit once you leave the service. For Army, only the medical and cyber branches have specific degree requirements; every other branch is filled based on the needs of the service that year. Also note that the academies are federally mandated to allocate at least 69% of each class into combat arms. 81% of our son’s class of 2019 was allocated to combat arms branches. At USMA, for instance, each cadet is required to rank the Army’s 17 branches in order of preference. USMA attempts to place each new officer into one of their top three choices, but there is no guarantee that you will get one of them. If you end up in a MOS (Military Occupational Specialty) that you find uninteresting, service can definitely seem “loooong,” as @gardenstategal so aptly put.
You should also make sure you understand the service commitment for each specialty as it varies, with five years being the least tenure. Medicine, aviation, and (soon) cyber will require ten years or more. The year our son commissioned, the commitment for cyber was upped from five years to six, but Congress is now considering increasing it to ten because there has been 100% attrition in the branch making it difficult to have cyber experts in the upper ranks.
Oh, and the reason our son is serving nine years instead of six is due to the two additional years + payback for his master’s degree.
This “free” education comes at a cost.