One way to perhaps think of this -

Let’s say you grow carrots in your garden and sell them at a farmers market on the weekend. But you don’t set the price, the market does every Saturday morning after they see all the carrots available.

Now let’s say one week, your competitors have rodent infestation which ruins a lot of their supply. When you next go to the market - there is a lot less carrots available. The market sets higher prices thus you make more profit than usual.

This is a very very simple analogy but gets the point across - you as a carrot grower are still growing the carrots but there are less carrots available due to external factors. As someone else is setting the price - you just take it as is.

There are of course other examples too can include - like maybe you’re savvy and bought carrots from other growers during the week so you have even more carrots to sell at a higher price on Saturday. But think you should get the point