I would not go that far. Chimps are adapted to living in forests, we are adapted to living on the open savanna. Upper body strength is essential to survival in equatorial rain forests where you spend the vast majority of your life living and hunting in the canopy. Endurance, the ability to cool your body efficiently, and being able to run for extremely long distances is essential to survival on the open savanna. Thus since our ancestors adapted to life on the savanna, we are excellent long distance runners, can cool ourselves quite efficiently due to our body shape and our ability to sweat profusely, yet have comparably little upper body strength as we had little use for climbing. In contrast chimps and bonobos have excellent upper body strength, a much higher proportion of their muscle fibers are fast twitch, and are physically much stronger because they are adapted to life in the tropical forest canopy. However, they don't cool themselves as efficiently, and they do not have as much endurance as running long distances is not as desirable of a trait living in forests.
The initial catalyst was the creation of the rift valley seperating our shared ancestor into two groups each living in their own ecological islands (one in the forest, the other savanna). Technically, chimps and bonobos are more evolved than we are as they have experienced a greater number of genetic adaptions since separating from our shared ancestor than we have.
Our greater intelligence arises from adapting to the harsh conditions of the savanna as well where collaboration in hunting and gathering was more beneficial, game was far more dispersed, and more knowledge had to be passed down between generations as to where game could be found, tool use, location of water during the dry season and so on.