As bad as it sounds being paid it´s actually a good thing. Once people learn you can make money out of Godot, many will flock to make new kits and assests with professional quality emerging eventually. Offer and demand will lower the prices as well as time passes.
Now I can see people getting annoyed at a Libre software getting lots of paid content since it goes agaisnt its spirit, but otherwise we won´t be getting pro level content. This also leads us to asset flips and many other evils, but I guess it goes with the job.