Evolution does not mean going from bacteria to human where "bacteria" would be the "least evolved" being and "human" would be the "most evolved" being.
Evolution means adaptation to the environment. Every species evolves to be the way it is because it can make a living that way. Our chimpanzee brethren evolved to be chimpanzees instead of humans because you can make a living as a chimpanzee (tree-living) in a forrest whereas our direct human ancestors could make a living in a more steppe-like environment (with less trees). That's probably the reason why they developed towards bipedalism.
Let's look at an example in human cultural evolution:
This (the dandy horse) is a common ancestor of today's bicycles and motorbikes.
This is how an early motorbike looked like:
This is how an early bicycle looked like:
This is how today's motorcycles and bicycles look like:
Now, today's motorbikes and bicycles are very different from each other but they are also very different from their past forms. You might here also ask: If bicycles have evolved into motorcycles that are faster and more powerful than bicycles, why are there still bicycles? The answer here is the same: Bicycles are still useful for use cases that motorbikes cannot be used for. There are still bicycles because there are still situations where they are the best vehicle to use for.
Also: While today's bicycles look more similar to bicycles 100 years ago than today's motorcycles do, you should not think, they have not been improved a lot over time. Today's bicycles have gearing, use lightweight materials, don't rust so easily and are improved in numerous other details to best serve the tasks bicycles are used for.
In the same way, today's chimpanzees might look more similar to our common ancestor than today's humans do, but they too have evolved a lot since that time and evolved so that they are more adapted to their way of living. For example, chimpanzees have greatly improved the Knuckle-walking technology over how our common ancestor did it.