This is an enormously wide question but the quickest way to give you an idea would be rephrasing as:

"Are cars not a solved problem? Why are there lots of different cars? Why is one faster than the other? What's different between them?"

I think the best way to approach the subject in an easy to grasp way is to ask Gemini or another frontier AI to teach you the basics, they will do a surprisingly good job and they'll be able to react to your questions with INFINITE patience.