I remember the 1984 Democrat fight to be candidate, and Walter Mondale's use of the Wendy's slogan against Gary Hary 'Where's the beef?'. I'm not sure there ever was much beef in the Presidential races I've seen, it's more an idea of something, not even a vision, that the candidates represent - freshness, anti Washington, anti corporate, change.
Now though it feels like both parties have become 'Not Them'. The division is simply othering, the long standing portrayals of them as Tweedledee and Tweedledum, have merged with the Cheshire Cat, and they have disappeared.
While this is not unique to the US, the political system with the President restricted in powers seems to have made this the prime example. I see interviews with supporters from both sides, Rep and Dem, and they would be lost and meaningless without each other. This is politics with the policy surgically removed.