So.... you think rattlesnake roundups are a bad thing, because there are fewer rattlesnakes now than there were in the past?
There are fewer rattlesnakes because the habitat for rattlesnakes is not what it was: most of that prairie (and the prairie dogs that populated it) is gone. It is intensively farmed/ranched with corn, soybeans, wheat, alf-alfa, sunflower/other oilseeds, cattle, sheep ..... without which, many people around the world, human beings, with families that love them, would starve to death. Simple as that.
Conditions change, and animals that can not adapt to the changes will cease to exist.
There are people that think we should restore the prairie, giving it back to the rattlesnakes and bison, by forcibly removing the people that feed a good portion of the world's population by farming and ranching that prairie (look up "Buffalo Commons") ..... such people are dangerous nutbags, IMO.
TheGolden Rule of Tool Use: "If you don't know what you are doing, DON'T."