What led to the massive migration of people from farms to cities?

A growing population meant more people were living in the city. As cities grew, more jobs were opening up for people to get a better pay, have benefits, and live a more luxurious life than living on the farm. Farms became known for difficult times, hard work, and little pay in the end. Farm kids seen this and decided they wanted nothing to do with tha farm business, so they moved to the cities. Farms were pushed out and sold out because of the urban growth that pushed them further and further out. The farmers that had to sell out couldn't get back in, so they had no choice but to go live in the city. Increasing inflation rates meant higher costs for the farming sector, which put profits lower and lower until farmers became broke, bankrupt, or just couldn't handle the financial strains anymore.

Today, more than 95% of today's population lives in the cities. Most will stay that way because of the much better pay, much more stable working schedule, more access to benefits and bonuses, and less hard work to deal with. Unfortunately, with a growing urban population, a decreasing rural population means less than 5% of the rural community is relied upon to provide food for the rest of the population that can't grow it themselves.