We have
- a serious mismanagement of resources via a nat'l resources deficit: https://www.activesustainability.com/environment/natural-res...
- a horrible distribution of food globally (as an example, the US wastes 40% of its food: https://www.usda.gov/foodwaste/faqs)
- more than enough land to go around.
In the words of Ludwig von Mises, "If the tailor goes to war against the baker, he must henceforth bake his own bread."
Society can maintain a balance in this way without population restriction. Greater population grants us the luxury of more specializations and ideally more free time and more comforts.
Even without my reasons, "you are wrong" suffices because the onus is on you to provide proof of an assertion, otherwise it's false by default. Providing proof of a negative is nonsense.
There was even a riot in 1973 that broke out by train commuters who were enraged that they couldn’t get to work due to striking train workers back when the JR system was nationalized:
Simply put, most people past a particular age are going to have reduced economic output due to frail bodies and weak minds.
Pensions are used by corporations to keep their spend and employee population predictable. It's lovely when it works out for the employee but its not the primary goal. I would debate whether its a luxury when you've locked yourself out of market growth in the hopes of a soft landing when older.
Also "If someone is fit and healthy" is far more than a series of personal decisions and age catches up with you fast. Once you also combine with that the changes in tech, and in the workplace in general, you'll see fewer and fewer options for that luxury pension