Mattresses have a bit of a different issue, in the sense that mattress stores have a (potentially exaggerated) reputation for being of ill repute (e.g. money laundering fronts) and having somewhat scummy sales tactics along the same lines as automotive dealerships (where Tesla, incidentally, would be an example of the "direct to consumer" approach).

The problem with DTC mattresses specifically (and DTC cars, for that matter) is the logistical hell on Earth that is actually getting that product "direct to consumer" (the products themselves are pretty huge and heavy), the higher pricetags (a mattress or a car is considerably more expensive than even a pair of eyeglasses, let alone razors or soap), the inability to reasonably handle returns or repairs, and the inability to "try before you buy" like you can in a brick and mortar store or a dealership.

Tesla worked around some of these problems by having actual physical storefronts/showrooms and service centers (which in turn caused issues in states like Texas that disallow auto manufacturers from owning/operating their own dealerships). The only DTC mattress company I know of that has physical storefronts (at least where I live) is Sleep Number, and it's one of the incumbents.