We built combat planes with silk & dope for years before Monokote, etc came on the market. Dope drys pretty fast. You can build up five coats in under three hours. It only take a couple minutes to brush on a coat, then you have 20 minutes or so to work on something else.
When we invested some personal effort in the planes, we weren't so casual about wrecking them.
Finally, the Missourian was designed in the days when The Nats ran by the old "points" system. You flew two matches and your final score simply the sum of those two matches. Riley Wooten won some of his championships under that system. While not exactly fair, it encouraged quality vs quantity, and it got a lot more entries because you only needed two models.