If politicians just voted the party line, what's the point in voting for them? They literally serve no purpose if they don't use some independent thought and cognitive thinking about whether the impact of the vote will benefit the electorate in their district.
I think you miss the point of Democracy, son. What you're looking for is a dictatorship that changes direction every 4-8 years.
By the way, DeVos still won, so what's the problem?
Does this independent thought and cognitive thinking exist only among the Republicans? We very rarely see any of the Democrat senators or House members voting for the measures introduced by the GOP.