system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do people say that supply-side, or trickle-down economics don't work?

It seems to be often stated as fact, but it kind of seems like something that can't actually be proven without hindsight?

EDIT: What do people specifically mean by "It doesn't work".
gpt
Imagine you're a baker. You know that every day, 100 people will come in to buy your bread. You can meet that demand with your current equipment and staff. Then, one day, you receive a tax break. Would you use that money to hire another employee or increase your oven space? 

If you're a responsible baker, you wouldn't. After all, you can meet the demand with your current staff and equipment. Supply-side economics doesn't work because in the real world, demand doesn't rise to meet supply. Supply follows demand.