Why aren’t transactions cheaper than the cheapest?

Considering that the GAS price can’t go below 1, at current gas used for a transaction (21000) the price of a transaction is about $0.03. Other contracts will spend a lot more, like a DeFi swap at 30 cents. If we want to reach max adoption and market efficiency, fees need to be able to approach to cero.

Why not decrease the denominated gas cost by a factor of 6 so the gas price has a million times more to decrease? So for example the gas used for a transaction will be 0.021 and the gas price will be 1000000 GWEI to match today’s USD cost at 1 GWEI price.