There aren't millions of people who have a lot of money to spend on products/services.Lots of (millions) people have this problem
They are willing to pay a lot of money for the solution
The average person has little money. Rich business owners have a lot of money. So you can either provide a small amount of value to millions (B2C - think Netflix), or a large amount of value to thousands (B2B - think Salesforce).
Either works, as long as there's real value.