This happens less where the FOSS choice is a drop in a sea of established proprietary packages (FreeCAD, KiCad, Godot) but way way more when they have already established themselves as the popular pick (OBS Studio, Blender) so they get flooded by less tech-savy, more casual users that don't really see the value of open source other than they don't pay for it.
"Normal" people have always had stuff given to them for "free" (either "you are the product" or built-in licenses like Windows) so they don't realize the goodwill and sacrifices that FOSS goes through.