I'm with Peter on this argument. I have had some nice blade ground coffee, in fact I had to use it on vacation in Kauai recently and if you use certain shake techniques and a good white paper filter, you would be forgiven if you mistook that I had used a Baratza encore burr grinder. everyone is entitled to an opinion sure but 3 week stale coffee is about as dead as cardboard no matter what grinder you used, you could stretch it if you froze the grinds but....blade grinders are cheap enough and they work well enough for white paper drip coffee.
On the challenge I have done that many times, the major differences come if you use a swiss gold filter, you definitely get more fines/sludge and forget using a french press. But most people getting preground are using screen filters from the store or paper filters...often brown yucky ones. the white paper filters seem to forgive a lot of sins. Currently I am using a Mazzer Super Jolly with brand new burrs, a cunil Tranquillo, and a Baratza sette 270 W, I have had several blade grinders, several Baratza/Solis burr grinders...a Bunn LPG and I have had lots of coffee from Chris' Ditting.
On that note- the argument is fun but goofy. No one is arguing which is what etc... Customers want pre ground coffee give customers pre ground coffee. If they are open to hearing about grinders share your opinion.