It's not that mass-production kills quality or "intangibles". We don't have to assume boutique products have a quality advantage. It's just that scale is most effective on price, and price sensitivity is not linear. Once products are cheap enough, price discrimination stops being decisive.
> The true-differentiation strategy seems to work best when scale, despite its efficiencies, also introduces blind spots in areas such as ... intangibles not entirely consistent with mass production and standardization.
That isn't really what's going on. Even if the big business is good, and scale is quite useful, there are many, many small competitors. All of the competitors are making products, and some of them are likely to be exceptional. So for the big business to stay on top, scale has to be helping a lot.
If there are 100 beers on the shelf, and one of them is a mass-produced, and the mass produced one is not #1 in quality, you don't have to assume mass-production hurts quality. It just that it didn't help enough.