Earlier quoted context omitted.
There is no constitutional provision that would ever allow abolishing the Senate. The Constitution of the USA prohibits any amendment that could change the disproportionality of the Senate.
Technically it says that "no state, without its consent, shall be deprived of its equal suffrage in the Senate" so the Senate could presumably be abolished by constitutional amendment if all states agreed. (I wonder about replacing the Senate with another legislative house and giving the existing Senate largely ceremonial responsibilities without formally abolishing it -- would that count as depriving the states of e…
The phrase "the Constitution prohibits this amendment" doesn't make any sense because an amendment to the Constitution cannot by definition be unconstitutional.