Nobody even thought the thing would chart top 20 in the first place.
Really? I'd like to see an example of even one person posting they expected this game to miss the top 20 in the UK first week.
8th position in a week like this is really low. Admittedly it likely sold a significant portion digitally.
Dreams is going to be fine, there's no need for the concern trolling. It has a built in viral life, when people start sharing their creations (which has already started happening). Plus Mario Maker and LBP were both big on the streaming circuit, and Dreams probably will be too.
How often does this happen where a game opens to really low sales but goes on to become a viral sensation? I feel like it's extremely rare. The much more likely scenario is this game will recover somewhat but still end up with mediocre sales.
Will wait and see more regions before judging though.