There are a number of external sales channels: franchises, affiliates, referrals, VAR/inter-connect, systems integrated, agents/brokers (to name a few). It works for more industries than just telecom, real estate and insurance.
All those models are for Sales. Remember though that isn't the same as demand or lead generation or any marketing.
It is important to note that most sales channels simply supply demand with sales activities (that can be confused with order taking). They do not drive demand. They do not create demand in the buyers. That is supposed to be done by the vendors, like IBM, HP, Cisco, Comcast, Verizon Wireless, AT&T. But do they drive demand?
These named vendors are some of the biggest spenders in marketing, especially advertising. Big Spender doesn't always translate into Effective Marketing. Branding or awareness campaigns are not lead generation.
The problem is in Marketing. (Not just because that is what I do as a consultant.) Besides telling a good story to position your product, there has to be a component that produces demand for it.
The companies in the price and spiff war might be failing at marketing. Just buying the sales that they can. That doesn't result in more leads or more demand. In fact, if you shut off the spigot (SPIFFs), you might be shutting off sales.
Think about cellular plans right now. For most people, it is about "Good Enough". Not the best.But Good Enough. That is the problem VZW faces right now. The best just can't command the same premium anymore.
Think about Internet access. Broadband is good enough. Except when it is down or congested. Except when your speeds or throughput suck.
[How do you market to people settling for good enough?]
For most people, it is about good enough.
Dropbox, Slack, minimal web security - good enough. Until it isn't. People make a mental trade off. [Remember, sales is emotional and buyers use facts to support their emotional decision.]
For example, take security, where is the demand? Every enterprise needs it. Companies get hacked every day. It costs companies upwards of millions of dollars (billions for some data breaches.) Yet the cost benefit analysis says "we will risk it".
The channel cannot manufacture demand. That isn't what they do. They sell to people who want to buy. And they sell them what the customer wants, not needs.
Think about that.
In a similar vein, you can read about What Pain does UCaaS solve?