The cloture rules have only had significant changes twice in history. Once in the 1910s when they were instituted and later in the 1970s. The fact that the senate requires unanimous consent has nothing to do with any purpose but is basically a quirk of history that the senate never got rid of the unanimous consent requirement. What we call a filibuster today is just a use of withholding unanimous consent to block a motion that would otherwise pass with a majority vote and isn't related to the use of the filibuster in the 19th century.