20-Year Prospect
While some people might wish that the U.S. Senate would just disappear, or possibly get deported to Mars, the "World's Greatest Deliberative Body" will continue deliberating for the foreseeable future. After all, this is one half of one of the three central pillars of government: the Niña, the Pinta, the Santa Ma—sorry, no, those are Columbus's ships.
Of course we're talking the Executive (President), Judicial (Supreme Court), and Legislative (Congress) branches here. If one of them goes, all of them go, so unless we devolve into a Mad Max-style method of governance involving crazy car gangs, you'll probably still be able to run for office.
Elections themselves are always changing. Once upon a time, The People didn't even vote for senators, who at the beginning couldn't be minority or female. Now, not only do we vote for senators, anyone of any background can run for the job. Maybe in the future, we'll even put limits on how long they can stay in office.
Oh, senators actually have to vote to make that change? Never mind.