Lol, do you think history is only the last 4 years? They’ve had more than 50 years and multiple instances of having the supermajority.
You also cited that they’ve purportedly had several instances where they could have passed it at will when there has been realistically 1 viable time just 4 years after the original SC ruling.
A brief history of one of the biggest obstructions and also notably important tools at the disposal of the Senate. Interestingly enough one of the few times that the rules on it where changed actually was at the behest of the Democrats to allow for placing judicial nominees without the Republicans getting in the way. Actively doing away with it or making significant modifications has been kicked around for a while but outright removing it would all but nullify any input by the minority party. By forcing a 60 vote barrier to things you set the table for either working with people of different stripes (not a bad idea, we did use to get a lot more done that way) or if you happen to be in a space to have those 60+ all yourself then you can consider that a free ticket and strong demonstration of the will of the voters.
Do you think their corporate sponsors accept these kinds of excuses?
I’m sure that they’re probably held to a higher standard of performance than their Republican counterparts who tend to come from poor states with low educational standards. The R’s can be bought off for a relative bargain price to be sure, so less pressure to get on the ball.