"Unlimited" is always a marketing gimmick, and they'll always contact you like "hey I noticed you're actually trying to use the thing you paid for you need to stop or we'll terminate you". Along the same lines: "Lifetime license" means 5 years, and "All-You-Can-Eat Pancakes means Four Pancakes."
I used to work at olive garden, it is true that we were told to give less on subsequent bowls (can't tell you how much was wasted where people ordered a second or third bowl and took like two bites) but not coming back around after... that wasn't something we were specifically told to do in my experience, probably just had a lazy server.
One thing is the unlimited soup and salad was like $6 and some people would only order water, get like 4-5 refills on soup/salad/water and then tip like a dollar. That is one whole table for an hour+ I could have had sat with someone else who wasn't being stingy as hell.
On the other hand, tipping culture sucks the company should just pay a living wage instead of the like 2.50 an hour they pay.
You nailled it in the last paragraph. It is important to not get angry at customers. It isn't their obligation to pay you a living wage. Secondly, the company chooses how much the meals are and indirectly how much they rent their tables per hour. If it isn't viable, they should increase prices.
Customers may be struggling. Could be their first meal out in months. The company invited them in with these cheap prices.
Tipping culture is like "hey, come in, eat cheap. Oh, and please pay our staff on the way out." You are an employer, not a table rental company.