Instead they are supported by ads, and it looks like Google will be adding more ads to Google Maps in the future. This will come in the form of what Google is calling “promoted pins”. These pins are basically pins of business locations that the companies have paid Google for to appear in Maps.
As you can see in the screenshot to the right, Walgreens has paid Google to appear on the maps and their company logo and a purple pin will show where they are. When users taps the pin or logo, it will display information like ongoing promotions, or maybe even offer up coupons for items that users can use when shopping at their store.
These ads could also change the way you search for things, like asking Google for cafes near you could result in cafes that paid for their location to be listed to appear first, like how regular ads are displayed in Google search.