The important question here is why human beings developed superior intelligence. We don't have a definitive answer for that, but we do have a number of good theories. It's not our big brains, our opposable thumbs, our upright posture, or our tool-using that vaulted us to the top of the food chain. We had those things for a couple million years, in all likelihood, and for the majority of that time, we were living in the shadows, terrified of being eaten.
What is it really that produced intelligence? A lot had to do with food. Some researchers believe our original niche was that of a scavenger: Homo sapiens wandered around the savannah and waited for apex predators to finish up with their carcasses. When they were finished, we'd descend upon the picked-clean body and use our rocks and basic tools to break open the bones and extract the nutrient-dense marrow. Just like the niche of giraffes is to reach high-up leaves, the niche of early Homo sapiens was to scavenge for bone marrow. This scavenging required tool-use, and more importantly, it required cooperation. Human beings are not biologically superior to other organisms: we are socially superior. We learned how to work effectively in groups, first small, then large. As our tool use and cooperation enabled us to move from scavenging to hunting, and then to hunt larger and larger game, we collaborated in post-hunt planning sessions that very likely generated the first languages. (Hunting is actually not a good time for language--better to gesture silently--but planning and celebrating post-hunt is perfect.) Languages are indispensable for cooperation and abstract thinking.
Even more important to cognition was the domestication of fire. Not inherently because of fire's utility as a tool, but mainly because of its tool as a time-saver. Chimps spend 5 hours a day chewing raw food. Imagine if you had to spend that long, or longer. Instead, you can wolf down cooked meals in a matter of minutes. Cooked food not only allowed for increased productive time during the day (less chewing = more free time), it also allowed for the shortening of the intestinal tract (cooked food = efficient nutrient absorption = shorter intestinal tract). This was critical in the development of the brain. Why? Because digestion and cognition are both extremely energy-intensive. Allocate less energy to digestion, and you've got so much more to put toward cognition.
There are other considerations in the evolution of intelligence, but these seem most relevant to your question. With infinite food, what pressures would exist pushing early hominids toward cooperation, tool-use, and fire domestication? In addition to figuring out the logistics of where this infinite food is coming from, you'll probably be interested in determining whether it needs to be (or can be) cooked.
(If you're interested in the evolution of human beings, I highly recommend Y. N. Harari's Sapiens, from which most of the details in this answer are sourced.)