Because of evolution. Throughout millions of years we've developed into the smartest beings on earth. Were capable of thinking and have thumbs! 2 things animals do not have.
Most animals can't manipulate the tools needed to make the machinery or the machines themselves. They are also quadrupedal for the most part. That means that, when they want to carry something, it has to be in the mouth. That is not conducive to the development of speech, which means less cooperative effort to make machinery or the passing along of the knowledge of how to do so.
Yeah I couldn't drive home from the bar last night so my dog picked me up and drove me home. He also runs the car pool every morning for work.
We evolved to have large cerebral capacities. Long story short, we learned how to use tools like rocks and sticks and came up with new ideas and make more stuff while we evolve even more to have larger brains. The reason as to why it's only us is because other animals are not bright enough. There are exceptions though, like otters.
We aren't. Lots of different animals use simple tools or like Beaver have extravigent dams that would take engineers a lot of work to figure out. To be able to do what we do today took us thousands of years to learn from generation to generation. From the day a beavers born they know how to build dams.
