Like H1B Visa Quota and Caps, there is no such for people visiting with B1-B2 Visa. The reason for having a quota is because of this Visitors Visa, the United States of America is generating income. Allowing the people from Business class to establish industries in the United States, which ultimately creating job opportunities to the people. If the money is coming from foreign countries, who would say no to it. On the other hand, every year the United States of America generates a huge income from tourism. Allowing tourist from all over the world, Department of Tourism is the USA creating a large-scale job offers directly and indirectly to the people living in America. Taking these things into account, there is no Quota for Visitor Visa, i.e., B1-B2 Visa.
If you have any plans to visiting to USA with Visitors Visa, do follow AfterPassport.com. You can find all the information related to Visitors Visa, i.e., B1-B2 Visa. For any other or clarifications in regarding to the B1/B2 Visa, please comment below. AfterPassport.com is always happy to help you