Broad jump is a two footed, stable platform movement. In common terms, that is a more rudimentary/lower demand movement in regards to plyometrics. Jumps in athletics are all single-leg movements that require strength, coordination, and stability. Just like in basketball, you can have athletes that feel more comfortable rising up off of two feet, versus one. Genetics, power, agility, and coordination can all have a huge impact on an athlete ability to execute certain movements.
You mentioned long jump in your post, but it is an event that favors speed. Your best long jumpers will have great speed, or at a minimum, good sprint mechanics. I have known athletes that could do a standing 360 dunk (pure vert), but had a hard time managing those forces off one foot + moving.
You might have a good foundation in your general strength and jumping ability, but are lacking in max velocity, sprint mechanics, and technical areas regarding your events. In order to run fast and jump far, you need to be able to be in the "right positions", exerting force into the ground correctly.