Putting your photography work on stock agency sites will probably never become your primary source of income. But, it should be considered a viable source for creating "some" income. And, you will have more chance of creating that income as long as you keep adding photos to your stock agency. But, you still need to conduct your business in a way that gets those who lease or purchase your photos to come back for more. Like almost all businesses, photography is a business that needs repeat clients to survive.
I know that I will need to add a few thousand more photos to start showing a useful income from my stock photography. I currently have around 800 photos on my Adobe Stock site. Most of these are photos of community parks in the Las Vegas Valley. My target market for these is rather small, and I am surprised every time I sign on and another purchase of my work has been made. I plan to use them to help me create a "stay local" market using another specialty.
Currently, I hope to spend a couple of years traveling to photograph parks, preserves, trails, memorials, monuments, and museums all over America. This is my bucket list work. But, I know that someday I will want to do far less traveling.m my work. I also have around 100 photo nature photos on my Alamy Stock site. And, yes, I know that both sites are going to need several thousand more photos on each site to really start showing an income. However, like most people, I like to eat. So, I need to produce an income. That is why I am preparing to go "old school" with my marketing program. It is my opinion that although the internet is a great tool for marketing your work it does lack the feeling that personal contact can give your business.