The aim for the launch price of the entire rocket is to be around 5 million (once it's fully re-usable and in production). Basically the price of fuel and maintenance.
So something might be off with your assumption of 1500 usd / kg.
Yes, it's based in the real world. This was the Falcon 9 launch price that I could come up with in the amount of time I was willing to spend on a shitpost. I agree that launch prices will continue to come down, but launchers will always be mass-constrained and launching lead spheres into orbit will never be a practical solution.
So something might be off with your assumption of 1500 usd / kg.