Independents have been all over the place, they swing wildly between parties. Harris did win the independent vote last year 49-46 over Trump. That wasn’t enough to over come the huge drop in democratic voters that didn’t show up at the polls.
Ahhh yes, the particular Dems who (A) remained lofty in their principles or (B) were pouty because Biden wasn't perfect and neither was Harris, or finally (C) the Dems in Name Only who really wanted to keep on "teaching America a lesson" and the (D) lazy and complacent who didn't think it would matter.