Why is the concept of taking space lost everywhere below GM?

Lots of players are stuck in metal ranks and diamond simply because they don't understand the concept of proactively taking the space away from the enemy team before they have a chance to take it themselves. I constantly see teammates that should know better, especially by their hour count who insist on sitting on the objective (including bot and payload) instead of moving up to take space and finish off stragglers or deny the area that will be the most difficult to push towards if the opposing team takes it back.

Hell I often see players that have yet to comprehend that when you are on offense, that it's good for you to sac wave for picks since you have the respawn advantage. It seems players genuinely can not work with windows of time that are as generous as 5, or even 10 seconds and more.

It's infuriating that these players will consistently argue as their only communication, ignoring that their lobby is doomed because of these bad habits.