It sounds like what you are asking is how do you systematically map out the various players within an industry which is essentially what a value chain demonstrates.
What you may be struggling with is even being aware of the various intermediaries involved in the value chain.
For some sectors this is more obvious than others, and is a classic case of an unknown unknown, e.g. you may not even know you don't know there are a whole group of intermediaries in the telecoms market who sell airtime to MVNOs (virtual mobile networks).
I would recommend starting top-down and getting the basics right by thinking about the fundamental steps a product must take to reach a consumer.
Let's take the example of the Electric Vehicle charging sector.
- End-user - a user with a car that needs a charger whilst driving down the highway
- Charging station owner/operator - there needs to be a charging station operator for the car to use. The owner may even be distinct
- Charger owner - whilst Tesla may build the charging infrastructure, own and operate the stations, for non-Tesla chargers, there may be an intermediary operator who actually owns the charging points and leases them to the station owner. The owner would assemble the various parts of a charger to create the full stack.
Two Inputs into the above
- Charger manufacturer - BMW are probably not building their own plugs but buying them from a supplier. The inputs to the charger manufacturer will be:
- Electronics supplier
- Raw materials supplier
- Assembly factory (outsourced)
- Utility company / battery manufacturer - The station owner would need to connect the charger to the grid which is where the utility would come in. Similarly they have an on-site battery to store excess energy.
- Raw materials supplier
- Assembly factory
- Energy production company
You can see by thinking through who gets what from where, you can figure out what the value chain may look like in a top down way.