Because factories was the first time a establishment had been made that allowed people to labor inside, instead of outside in the unpredictable weather. This fact plus many others opened doors to modern day labor or work employment, which changed history.
Most of the population in England migrated to cities in the late eighteenth century because of better jobs. In the late 18 century, people forcibly driven from the land into factories by 'enclosure'. Landless, the agricultural labourers who remained were powerless to prevent explotation and were therefore forced to work for long hours for meagre, irregular wages.
The job market is studied and reported on by the department of labor:)
