Siblings are never equal. Despite every parent's best effort (or their worst effort) to keep things fair, no two kids will ever be exactly alike or have the same needs. Take it from me, a self-reliant independent child whose sibling was very needy. Did I ever get much help from Mom and Dad? Certainly not, because I didn't need it as much.
However, being an independent child comes at a cost. Without your parent's watchful eye and guiding hand, you're left to do everything solo, fending for yourself as you become an adult, slowly resenting your seemingly childish sibling for all the aid they're privy to. Naturally, with unequal resources, siblings can feel a wedge driven between them, growing into their adolescence and finally adulthood with a chip on their shoulder against the other, imagining how much easier the other has it.
However, being an independent child comes at a cost. Without your parent's watchful eye and guiding hand, you're left to do everything solo, fending for yourself as you become an adult, slowly resenting your seemingly childish sibling for all the aid they're privy to. Naturally, with unequal resources, siblings can feel a wedge driven between them, growing into their adolescence and finally adulthood with a chip on their shoulder against the other, imagining how much easier the other has it.