I'm not saying that you can't be creative as a player. But the burden of the bulk of creativity is on the DM. You said this:
In that quote, you acknowledge that it's less work to play than to DM. This is because there is more burden on the DM to come up with the content of play. As a player, you only have to worry about your character and how they react to things.... you don't have to be as proactive in order to take part in the game.
Yeah, it's in imperfect metaphor. Of course players are contributing. It's just the way they do so is different.
We can shift the burden of driving the game... of being the creative force that is proactively determining the events of play... to the players somewhat. This typically results in more player agency. It's the players prompting the DM, who then reacts. This dynamic, though present in all games, is more present in games with higher agency.
I think that D&D 5e allows for a bit of a range here, and that's what I've been talking about throughout the thread. I believe other games offer more... actually, require more is likely the better way to say it... but I've honestly been trying to stick to 5e only in this thread. As much as possible, at least.
I think you mean being a player is not less creative? I think there's a difference between the level of one's creativity, whether player or DM, and the amount of effort that needs to go into making a game work. I'm talking about the latter. You would seem to agree given your description above about being "grateful that someone else is putting effort into creating the world and making it come to life when I get to play".