The answer is "yes" those senators probably would change their votes. If Biden and Harris and over 80% of Dem voters all say they support $15/hr, then if they want to get reelected, they'll vote for it. If they don't plan on running again, it might fail, but there might be a Josh Hawley or a Marco Rubio to still get them over the line. And if it doesn't happen, it still is a good thing for Dems, because the American people (who overwhelmingly support $15/hr) will see the Dems fighting for it. There is ZERO downside to overruling the Parlimentarian and fighting for it - IF and only IF the Dem leadership really wants it. They don't (Lauren's point) which is why they don't fight.