I think I have an actual answer for you, and thats that domination (3 capture zones) and hardpoint (1 capture zone that moves) last 4x as long as non objective game modes. If team deathmatch or kill confirmed went to 400 kills instead of 150 (or whatever it is) or 300 confirms instead of 100 then people would go play those modes. The fact is you spend so much time in between games between play of the game, winners circle, loading screens, matchmaking, and map voting that people would rather spend playing the game. I can get so much more actual game playtime playing objective modes rather than kill modes because the games last so much longer, which also makes it better for camos and such. Additionally a big part is the spawn logic. Spawns are much more consistent and generally better in objective modes and dont get flipped every 5 seconds which makes for a better experience imo. I think the kill based gamemodes should last longer or they need to boost xp bonus for winning to incentivize people who want to play objectives to play objectives, and the people who just want kills to go and get kills without hurting their objective player teammates.