Lean-Agile is still new to many buyers/customers, both internal and external, wanting courseware. You may be able to influence them into applying Lean-Agile. You need to aim for a relationship with customers that is strong enough that they will give you a hearing if you propose why this approach can help them. It helps you too, and is win-win, but many customers prefer to hear primarily how Lean-Agile helps them.
Some buyers are open to it if you can show them how it will help them. Some are opposed to changing to some new process when they use the waterfall method with all of their other stakeholders and suppliers. Some may not feel they have the political capital to lose if they view your proposal as an experiment and worry you may not succeed. In situations where you do more than submit a written proposal, do more to persuade them. Ideally, meet face-to-face or get on the phone. Asynchronous messaging with email and text messaging is insufficient for this persuasive task. We have had many customer discussions in person and on the telephone about how this can help them and how it will impact their subject matter experts (SMEs).
The buyer/customer individuals who are open to Lean-Agile also need to ensure they come through for their own boss and stakeholders, so as long as they see consistent progress, this can work. The iteration demonstrations are trust-reinforcing as the customer sees all the plans turned into working courseware increments earlier in the process than they might have seen otherwise.
The software industry is awash with Agile concepts after 10+ years of use, and it seems that most everyone in the software arena is familiar with Agile to some degree. However, the training industry did not come up with this idea, and movement to Agile is occurring more slowly. So even when you get your buyer/customer to agree to Lean-Agile, you may still need to help them during the periodic reviews with their own management and stakeholders to help them understand why you’re using this approach and how it helps them.
Because of the many proponents pushing various specific Agile methods rather than focusing more on the principles, your buyer/customer may also have some misconceptions about Lean-Agile that you will need to listen for and address appropriately.