There are many things in play here. We humans are social animals and we still have a lot of vestigial stuff when it comes to establish our relative social rank

There are many things in play here. We humans are social animals and we still have a lot of vestigial stuff when it comes to establish our relative social rank. The people you perceive as being less competent maybe appeal to those vestigial "leadership traits" more. Superficial stuff such as your voice, your posture... and less superficial stuff like how you express yourself, verbally and non-verbally. You can try to work with a voice coach, you would be impressed with the results. Then, maybe you are a victim of your own success. Being too effective in your role can make it harder for you to be replaced. Support is required for getting promoted. Support would be taken for granted in a meritocracy, where people recognize and honor merit, by supporting people that deserve a promotion or stepping aside if a better candidate comes up. But not every organization is a meritocracy. It is not only about doing a lot of work, but also about being able to take the credit for that work. If you were an individual contributor in a team, most likely the credit got distributed among the team or your manager took a good chunk of it.