So if you know the audience is shrinking, the budget shrinks accordingly.
So rather than try to reach more people, you throw your hands up and say "welp, nothing we can do here. Just keep dropping off phone books at people's houses and hope for the best. What's that? Printing costs have gone up? Make the books smaller!"
Don't invest in your product. Don't try to build your brand. Don't try to grow the business. Just keep doing what you're doing on an ever-shrinking budget. Surely this will lead to success...