There's only so much food people can grow on planet Earth, so it remains true, even if the number varies depending on the means available for producing that food. So yeah we can grow more food than people thought decades ago, but the Earth and the energy available to it, along with arable land are still finite.
Empirically, we now get more than 3x the yield per land area than 1960, and the trend is steadily rising (see graph link below).
Your argument is that it can't grow to infinity, which is probably true. But there is nothing indicting we're close to any hard boundaries.
https://ourworldindata.org/grapher/index-of-cereal-productio...