Up until that time, photographs were not printed on paper, but on glass, copper or tin sheets - daguerreotype portraits. It wasn’t until the early 1840s that technology began to advance, allowing photography to become a more commercial art form and even then it would be another 20 years or so before the average couple would hire a photographer - most often to show up the day of the wedding and take a single photograph. Wedding albums would not come into being until the 1880s, and color photography wasn’t a possibility in the beginning of the 20th century. Even then color photography was not considered altogether reliable until the 1950s and was in large part not a part of professional photography.
Up until the end of WWII, wedding photography was a studio art form - regardless of the advances in technology. It wasn’t until soldiers began coming home that two things happened. There was a surge in weddings known as the “wedding boom” (which coincidentally occurred almost exactly a year before the “baby boom”, and many soldiers returned home in need of work.
By this time, cameras were film-based and portable - and flashbulbs were smaller and easier to transport. Suddenly photographers were showing up at weddings, unannounced and without a contract, and photographing events on spec with the goal of selling the prints to the bride and groom after the fact. This newfound competition and the potential to earn lured traditional wedding photographers out of their studios.
With all these advances in the industry, most photos were still very staged - even the “candids”. The modern approach to capturing a wedding did not fully evolve until the 1970s.