Sophie SchmiegA very nice explainer why "if you're so worried about quantum computers, why haven't they factored 21 yet?" isn't a very convincing argument. Look at the labels of the graph, and how extremely close the various lines are for factoring 21 and 2048 bit numbers. Polynomial scaling remains polynomial, unfortunately, and by the time you can factor 21 you're almost ready to break RSA.
poleguy looking for lost tools@sophieschmieg A physicist I used to work for said quantum computing is very good right now for getting grant money to develop very nice ADC's and detector circuitry, which is useful for astronomy and particle physics.
He admitted when I pressed him that he agrees that the actual computing part is complete bunk and going nowhere.