Vertical products start with their median customer.

New horizontal platforms (e.g. mediums) start with a weed species unlike their median users to kickstart the ecosystem.

Vertical products have a singular network effect of strength in numbers.

Horizontal platforms have multi-layered, multi-dimensional feedback loops, which scale with the combinatorial possibility of the building blocks.

They scale much faster, allowing the platform to continually ratchet up the kinds of things it can accomplish.

Vertical products just get better and better at their vertical niche.

They have to be expanded horizontally through direct, intentional effort.