Why don't we install a knob that we can turn that effectively limits trading to X seconds precision?

One day we may decide to turn that knob from the millisecond range to 1 second and see what happens. If it's bad, we can always turn the knob back.

> If it's bad, we can always turn the knob back. Sure, but by then maybe some people or organizations have made/lost millions. So we can't realistically experiment with that (even though I would absolutely love to)

If a businessmodel is questionable from a societal viewpoint, then they shouldn't be surprised that some regulation hits them. See for instance Airbnb, where the businessmodel has become impossible in many cities already.

We kind of already are doing this: https://www.bloomberg.com/opinion/articles/2019-08-01/why-ex...

it would make more sense to first get rid of the penny rule.

I feel like we do know how much liquidity is too much, in the sense that the HFT traders are siphoning profits from value-seekers to rent-seekers. The total of their profits is the amount by which there is too much liquidity.

It's not necessarily clear whether it could be reduced to seconds of liquidity, or minutes, but it's clear that milliseconds is too short. The money isn't remaining in the market long enough to provide value -- especially when the market has already been made and they're just trying to figure out who gets the surplus between ask and bid.