One reason the internet grew as quickly as it did was because the capex was at the edge.

On the edge, the marginal investment (e.g. buying a modem) led directly to marginal value for the investor.

With investment in the center, there's at least one extra ply.

You invest, then someone else does something then value is created.

More indirect, less sure, a slower loop.

Systems with longer feedback loops grow and adapt much more slowly.