They likely would be successful in having me removed from the property at that time. And they would have given me some very good ammo to use in the resulting legal action, as at that point they would have made it clear that they are not willing to resolve the situation without being forced to by someone outside themselves. I certainly didn't want to deal with suing them and they certainly didn't want to deal with being sued...the business had a lot of other problems at the time.
Turning it from email/message/phone contact to in-person is an escalation. The other party can choose to reply with further escalation, or they can recognize doing so may result in further escalation. The other party has to decide if further escalation is worth it, and their ability to eventually fully "win" is part of that.
In my example, they were clearly in the wrong and they knew it. Escalating was not worth it because I could respond with further escalation that they would not likely win.
For a large corporation with a substantial legal team, that might make sense for many situations...they've already paid a baseline cost for the capability of near-continuous engagement with litigation of some kind. For many small/medium businesses, it can be a large additional cost. Then it becomes a question of "am I so willing to screw this person I owe money to, that I am willing to screw myself in the process?"
Showing up in person is a way of indicating you're willing to make it complicated and/or expensive to make you go away.
