Alan Voorhees wrote:
Brushed finished were used by carpenters because it didn't dry quickly. That allowed them working time to apply the finish to an entire room without having to worry about the solvents evaporating too quickly.
+1 to above comments by Alan V. Painters and carpenters will typically apply finishes by brush when using slow-drying products, such as oil/alkyd enamel, varnish, etc. Applying a slow-drying finish coat with a high-quality brush will allow the product to flow together before drying, thus eliminating (or minimizing) brush marks. Lacquer can also be brushed, but this requires fast work and a high level of skill; even then it must be polished out to remove brush marks.
But as Alan says, brush-applied finishes would never have been employed in a high-volume commercial factory. Or at least not in one past the very earliest years of the 20th century. In fact, many American manufacturers were applying sprayed-on finishes as early as the 1880's.