Kyrsten Sinema took a similar tact. Came out of the Arizona state senate making all the traditional progressive mouth-noises. Then immediately pivoted to Silicon Valley shill and corporate flake, the moment her 50th Senate Vote could be leveraged for profit.

I don't think it's a flaw in the individuals nearly so much as a flaw in the Senate as an organization. The institution was created by and for Plantation Owners, as a bullwark against large popular governments in industrialized free states. It's consistently served a narrow selection of rural mega-land owners and big state financial elites. Blanche Lincoln played the game and cashed herself out. But you don't get mad at the wheelbarrow for winning a game of Monopoly. It's a rigged game that rewards greed and backstabbing.