There is a lot in your comment I can’t really address, but I will touch on one specific line.

“Why supposed that humankind are any different?”

There are three level to address this on. First: is there a limit to the number of humans we can host on planet earth without massive losses in quality of life? The answer to that is yes, basically by definition. You take what is the maximum amount of food that can be made on earth, then divide that by the amount the average person eats. You will get a finite number there.

Second level: are we human anywhere close to that limit? There is no reason to believe that we are. About 80% of cropland is used for feeding animals (primarily cows). If people were to switch to plant-based diets we would therefore get a tremendous amount of new space to produce food. Also, about 1/3 of the world’s food goes to waste every year.

Third level: is there reason to believe we can adjust that limit? Yes, in fact we already have! Humans have greatly increased food production using science if you compare the amount of food we get per acre of cropland. Not to mention medicine.

If you don’t like food as the only metric, variations on this exercise that could be repeated for anything else you care to look at. There is no reason to believe that the sheer number of people is too high.