Knowing people who have worked in electronics retail before, the majority of "refurbished" PCs are literally next day returns that are brand new. If there was a genuine hardware failure or damage issue where it had to go back to the manufacturer, the manufacturer doesn't typically push it back to the retail outlet (they might sell it from their own outlet store like Dell does in this case). Either the person had second thoughts and returned the computer, or they bought it for someone but it didn't have XYZ feature or hardware they wanted. They can't legally resell it as new even if it's never been actually used in many places, but it's still in like-new condition so they can resell as refurbished instead of a more deeply discounted open box item.
I bought a refurbished Asus gaming laptop from Newegg maybe a year ago, saved close to $500 and half the accessories were still in the original packaging. Runs like a dream.