Why is it 3 strikes but 4 balls?

Excuse me, could you please clarify something for me? I've noticed that in baseball, the rule is often stated as "three strikes and you're out," but when it comes to the pitcher, they're allowed to throw four balls before a walk is issued. I'm curious, why is it set up like this? Is there a historical reason behind it, or is it simply a strategic decision made by the game's creators? I'd appreciate any insight you could provide on this matter.