A Deep Dive Into how Horizontal Platforms Truly Become Unbundled.
Good series so far.
1) The dimensionality is good analysis when the features vary by subnetwork. Definitely lends itself to vertical competition in subnetworks.
2) Network effects are a little more variable based on business I think, as local-based competition is very different for food delivery vs short term rentals. Another network to check out and think about in your analysis is FieldNation, a US-based platform for onsite technicians supporting PC/POS/Cable installs and maintenance. They seem to match high-capacity (invested in their features) while being a single vertical. Their "global" geography provides barriers to entry for local-only competitors.
One other platform is Rover, for pet sitting (they have a nice platform). You would think pet-sitting services are a collection of subnetworks, but building up supply is a barrier to entry and haven't seen an obvious competitor in the overall market , unlike Lyft arising to challenge Uber. Technically, you might say that there should be the potential for a competitor to arise in local markets to combat Rover...just haven't come across one yet.