Can someone explain to me why lead HAS to come from another element? Why cant it just… exist?

Some addition to my post: The computer I found is a Fujitsu Esprimo Q957. I’ve read online that they are very power efficient and don’t draw as much. I will probably run some lightweight task almost 24/7 and sometimes heavier tasks for short periods of time. A raspberry pi is for me too expensive for the average specs, even if it is very efficient. I think a upgradable pc or mini pc is best, because they are cheap, but can be easily upgraded without buying a whole new computer.