Democrats seem to forget what happened in 2016 when Hillary raised DOUBLE that of Trump with $1.2B and he raised $600M.
Biden so far has about $710M and Trump has about the same as 2016 with $596M.
If anything, Democrats should be concerned that they're basically only raising half of what they did for Hillary in 2016.
Biden has been raising more very recently, but over the course of the whole cycle Trump has raised far more. All that extra money has gone into building a huge ground operation which Biden does not have and will give Trump a big advantage when it comes to turning out the vote on election day.