I think it’s a little unfair compared to letting people put their orders on exchanges directly

You are guaranteed a price that is equal or better than what you'd get on the exchange. Why would you want to bypass that?

Well “the price” might be totally different if there were no off-exchange orders. But I’m sort of being a devil’s advocate... I agree with your argument in practice since I don’t expect to see such open exchanges anytime soon

> Well “the price” might be totally different if there were no off-exchange orders.

I'm not sure what that means, but there's no scenario in which you'd get a worse price. That would be illegal under the Reg NMS order protection rule.

https://www.investopedia.com/terms/o/order-protection-rule.a...

You won’t get a worse price than what the exchange says is the price, but that price Is a moving target; if all competitors could see all orders, the price would move. Idk if it makes a difference on average but it is a difference