That's partly true, but not all true. A simple majority does carry as a rule, except, as you pointed out, for treaties, conviction in the case of impeachment, and one or two other things.
But the hurdle is getting to that darn vote. That step (scheduling the vote on the underlying measure, even if it's for "right now") takes unanimous consent. Cloture is a substitute for unanimous consent to take the vote. The only thing required in order to delay a vote is to withhold consent to take the vote.
You are correct.
Unanimous consent gave birth to the filibuster.The cloture rule or agreement replaced the filibuster.
The difference between the two is that the filibuster took place on the floor of the Senate and was subject to the rules of the floor.
When items where passed in the committees by simple majority they went straight to the floor for debate and action.
The weapons the Senators who objected had to use was the power of persuasion and the filibuster.
The filibuster was self-limited by the physical requirements. I think the longest was 40 something hours. then the item had to be dealt with in an up and down vote by all senators.
All other Senate business had to wait until the item on the floor was dealt with one way or another. The Senate had to act on the business before it.
It was accepted or rejected by simple majority except for constitutional exceptions.
When they rewrote the senate rules and adopted the cloture rule instead of filibuster they placed a barrier between the committee and the floor.
They also raised the requirement for passage for whatever business 17 senators decided to from simple majority to super majority.
They also went from a procedure that was physically self-limiting to something that technically could be delayed indefinitely.
Hence you have a nominee who had passed the committee and had the floor votes being held by up 17 senators for four years.
The Senate by adopting the cloture agreement and allowing it to be abused has usurped the other branches and taken power unto themselves that is not granted by the Constitution.
They have said to the other branches ,if you expect to get anything or anyone buy us you had better be able to please 60 of us are forget it.
This is strictly against the Constitution.
I would like to see the cloture rule abolished and a return to the filibuster as it was.
Then the only time you would see this take place would be when it was really needed, not simply for petty obstruction type politics.
These old lazy blowhards like Byrd and Kennedy couldn't stand up for three hours much less thirty.
Certainly they wouldn't want stay away from the girls and the booze that long.