Depending upon where you live, the puppies you see at your local adoption center may not be local strays...but rather may be imports from elsewhere in the country. There are a few factors that set up the business model that make this a reality:
Entrepreneur drivers like Joy Harklerode make a difference in states where the economic hardship of paying for the spaying an animal outweigh any "greater good for the greatest number" concerns. She, and others like Rusty's Legacy and Brother Wolf Animal Rescue make the economics of animal rescue work by acting as intermediaries in the transporting of unwanted pups to states where there is an undersupply of adoptable dogs.
This is one example of making a business that aligns with personal values. Wanna see more puppy pictures? Visit Topic.com.
Source: "What Rescue Puppies Teach Us About Supply and Demand," by Peter Balanon-Rosen and Lizzy O'Leary, Marketplace: American Public Media, December 7, 2017.