Amazon calculates a product's star ratings based on a machine learned model instead of a raw data average. The model takes into account factors including the age of a rating, whether the ratings are from verified purchasers and factors that establish reviewer trustworthiness.
Great fit, comfortable and does perfectly what its meant to do. This is not something you are meant to run around in from the market to the airport to the bar and back home because if you do, it will fall apart pretty quick because this is a simple, well built house slipper, not a Nike jogger. No point blaming a product whose purpose is misunderstood.