If the Republicans didn't win in 1980 we wouldn't have the shitty Reganomics of today, so yeah, it was the most important election (that humanity lost) in history to that point.

If the Republicans didn't win in 2000, then it's arguable that the twin towers wouldn't have been destroyed, creating an excuse for decades of suffering across the globe, so yeah, it was the most important election in history (that we lost) to that point.

If the Republicans didn't win in 2016, then we wouldn't have had the worst supreme court in a century in power, wouldn't have politicized COVID, and would have had much stronger health care. So yeah, it was the most important election in history (that we lost again!) to that point.

If the Republicans weren't consistently horrible and on the verge of power, you'd have a point, but until they're gone, they're a constant threat to the country.