God, these numbers remind me of 2016...
Trump's not getting 38% and if Biden's failing to outperform Hillary's numbers then he's finished.
Trump's 2016 numbers were mediocre at best and Clinton lost because she failed to consolidate the anti-Trump vote. Considering the current political environment is quite reflective of 2018 and its trends, that Trump is President, and that we are in a serious crisis, I don't think it's unreasonable to say all Biden really has to do to keep defections at modern averages is simply keep the major gaffes to a minimum.