Because what we focus on we create more of, a scarcity mindset creates lack and an abundance mindset creates more abundance.
I chose a picture of lenses because in film, focus is also an important concept.
Where you focus an image directs the eye where to look. In life, where you focus your thoughts directs your brain to spend its energy there.
When you're working within a shallow depth of field, you literally can't see anything but what is in focus. All the rest is just blurry.
Its hard to make a meaningful image about something if it's a vague blur in the background.
In the same way, I can't create more abundance in my life if that's not what I'm focused on either.
Are your goals kind of blurry in the background? Is your your lack sharply in focus in the foreground?
Remember that what you focus on is what you create.