It is of course not at all certain that pre-1800 migration patterns would continue post-1800 as well, or that Swedish/Scandinavian speakers would be most likely to move into areas where certain Finnish dialects are dominant. The biggest driver of migration in the 19th century, especially its latter part, would be economic development and industrialization. Thus outside from the areas where there has been a strong Swedish-speaking presence, the numbers of Swedish-/Scandinavian-speakers would likely increase most in growing industrial towns and their vicinity, and along the railway lines that would get built. Even in the growing industrial towns, Swedish-/Scandinavian-speakers would likely not make up the majority outside the south-western and coastal areas. In the interior, in likely towns like Tampere, Varkaus, etc, you would see the formation of a Swedish-/Scandinavian-speaking managerial and professional class, but the most growth in industrial population would come from the surrounding, heavily Finnish-speaking countryside.