"According to consumer law, if the price could be considered reasonable and there was offer and acceptance of contract, Argos would be legally obliged to give me the console for that price."
Absolutely, 'reasonable' is the key word here.
From what I can gather, the law on this sort of situation is a bit of a grey area, but I'm going from the experience of a colleague of mine who bought goods from an internet site for around £280 when other retailers' prices were around the £350 mark, and was then told that the price was a mistake and that to get delivery of the goods he'd have to pay the higher price.
He contacted the Office of Fair Trading and was told that if the internet trader did not deliver the goods, he could buy the same goods from another retailer, and could then take the internet trader to court to get back the difference in price (plus costs), and would almost certainly win. The internet trader then backed down and supplied the goods for the originally quoted price.
This was because, and only because:
1. The internet trader had already taken payment from my colleague's bank account, so a contract was in place.
2. The drop in price could be 'reasonably' assumed to be a discount or promotion, not a mistake. Most judges would deem a price drop from £350 to £280 as fitting this assumption, but in the case in the article, a price drop from £379.99 to £89.99 would almost certainly not be deemed 'reasonable' and would not be enforceable in court.