"Completely wrong" is an exaggeration, would portraying a chicken without feathers be "completely wrong"? Of course not, if the overall anatomy is plausible, it would be inaccurate in one regard but not scientifically or illustratively worthless.

No, not all dinosaurs were feathered. Some definitely were not feathered (we have evidence of their scaly exterior, most impressively this armoured dinosaur specimen) while certain other clades definitely were, for which we have strong evidence, and thus species such as Velociraptor have been reconstructed with feathers even in the most broad-audiences-oriented media for over two decades. For many species it's uncertain. So no, many of the featherless reconstructions are still not wrong in that department, considering our current knowledge.