OP, many companies that rely entirely or mostly on Dominican customers have a decent to great revenue flow.
For example, El Encanto which is a department store chain with all its stores in Santiago brings in around US$40 million a year. Sure, that's not enough from which it would make anyone one of the richest people on the planet, but US$40 million is US$40 million. Caribe Tours around US$23 million. Ikea has a revenue of about US$13 million per year and technically that's a new business. Ilumel is shy of US$3 million. El Catador which is a wine store with all its stores in Santo Domingo is around US$9 million. Helados Bon over US$6 million. The movie theater at Galería 360 about US$1.3 million. Jardín Constanza (mostly flowers) about US$10 million. RH Mejía (owned by Hipolito's son and deals with the importation from the USA, distribution and even direct customer sales of several fruits such as apples; until his incursion into the sector apples were a luxury in the DR where most people would eat one only in the Christmas season and it was a fruit mostly purchased by the rich since it was expensive) a little over US$3 million. Baldom (mostly condiments, their products are in just about every supermarket in the country) around US$50 million. La Fabril (mostly vegetables cooking oils, one of their products is La Joya) about US$37 million. So on and so forth.
On the other hand are larger companies that depend mostly or entirely on Dominican costumers. For example, Grupo Ramos (parent company of La Sirena, Aprezio, Super Pola, Sirena Market, etc) has revenues of around US$760 million. Centro Cuesta Nacional (parent company of Supermercado Nacional, Jumbo, Casa Cuesta, Librería Cuesta, etc) is around US$580 million. SID (Next gas stations and many eatable products like La Manicera, they also own the African palm plantations seen on the highway to Samaná harvested for the oil in its nuts) has revenue of over US$1 billion and yes, it starts with a b. Cervecería Nacional Dominicana (Presidente, Malta Morena, etc) is above the US$380 million range. Banco Popular has revenues of around UD$737 million. Etc...