People love comparing layer 1 of Bitcoin transaction throughput to Visa, even though it makes no sense at all. Visa is obviously not layer 1 of the current financial system, it’s at least layer 3 if not 4 or 5 depending on what you consider a layer.
When you’re creating a new monetary system, the last thing you want is the foundation layer to be flimsy in any way. You want it to be as strong as possible. That’s why many of Bitcoin’s “competitors” compete in speed and not decentralization or security. You can always make the layers that are built on top faster.