Why did the land owners in California send out all of those flyers?

Simple, the more flyers the landowners sent out...... the more responses they'd get. Their advertising brought in far more job seekers than they actually needed (they needed 800 people and sent out 20,000 flyers), and because of that, they insured themselves that wages would plummet and workers would settle for less money because the jobs were in demand. It was quite the brilliant tactic...... those sheets of paper saved them a lot of labor wages!