The decline in the percentage of Americans who work in agriculture is due to advances in farming technology, not due to low pay. Now one person with a giant combine that didn't exist 100 years ago can do the work of tens or hundreds of people.
Depends on what you're farming - technology certainly has an impact with crops like wheat and potatoes - grapes, lettuce, melons, citrus, berries, etc. are a whole different story and require manual labor with technology having less impact.
