I've thought about this a lot. The totally unscientific conclusive I've come to is that it isn't about scale per- se but about the money and greed that tends to come with that scale.
As Acton once said[1], "absolute power corrupts absolutely".
There's something to be said for small, and there's something to be said for niche too.
Money usually optimises for advertising, advertising optimises for reach, and reach is the opposite of exclusivity or refinement.
There's some benefit to some selective markets, especially if they tend to focus money more than brains --- this is the notion behind virtually all luxury or high-end products, and was a role served by magazine publishers in the last quarter or so of the 20th century: a clear indicator of market segmentation and focus, combining both the magazine's own audience bias as well as geographic (and hence, socioeconomic) market differentiation. That's now largely moved to online and mobile.
As Acton once said[1], "absolute power corrupts absolutely".
There's something to be said for small, and there's something to be said for niche too.
[1] https://oll.libertyfund.org/quote/lord-acton-writes-to-bisho...