The major impact that the changing economy had on unmarried women was to create more opportunities for them to work outside the home. However, it also had the effect of causing them to need to work outside the home.
The economy was changing from one that was based on subsistence farming and small shops to one that was based on factories. In the old days, unmarried women worked on their family farms or in their family shops. With the coming of factories, there was less of this sort of work and more "formal" work to be had.