No, they went to assigned times after they reopened post-covid to try to space people out.
Look, if you can drive to the port then it's easy to arrive at your assigned time. I live near Port Canaveral and can be there during my assigned window. But next week I'm flying to a cruise in Long Beach. My flight will arrive LAX when it does and then I will take the Carnival bus to the port. I'll get there when I get there, regardless of any appointment time. So i should stand outside the terminal for 2 hours waiting for my time slot? Not going to happen. I'll check in when I get there, a factor out of my control.