When is a Scrum or SAFe project expected to generate revenue?

Think of it the other way around. The most important project is the Sprint, precisely because at least one Increment of immediately usable quality must be produced no later than the end of it. That's the mindset to adopt, and to encourage in others. It's a matter of innovation. The more Sprints are purchased, the more innovation runway there is for learning to build the right thing at the right time.

As part of Product Ownership, a Product Manager has multiple choices for "selling" and "releasing". There is no one single "correct" way.
I have worked with different clients in different situations, all using the Scrum framework, that might give some ideas:
A machine constructor used Scrum to reduce technical risks as quickly as possible. The end product could only be provided to users after extensive testing of the full machine. This first sale was only possible about 2,5 years after launching the initiative. Sounds like your case.

In another case, a software platform is provided to customers with a number of features. Customers pay a license fee. Depending the license there are more or less features available. Sprint after Sprint features are improved or added. There is no change to the licensing strategy. It is up to customers to upgrade their license if they want access to additional features. This is a totally different scenario.

Yet another case is a solution builder (both hardware and software), that typically partners with a company to build a solution for their problem. Later on the solution is extended with other features for clients with similar, though or slightly different challenges. In this case (irrespective of intermediate releases), the first client pays for their release(s), while other clients pay for their (later) release(s). Sounds more like your second scenario.

In the end it is really up to the Product Owner (a.k.a. an agile Product Manager) to decide when to release, and to decide how to get revenue; i.e. decide on a release strategy and decide on a pricing strategy.
These are complementary practices to the Scrum framework.
 

Hope this helps.
Feel free to shoot more questions!
 

PS You might be interested in my blog posts about the fundamentals of the Scrum framework. If so, please check out this page: https://boostyourscrum.com/professional-scrum-foundations-series/

Many thanks. 

So now I am aware that selling incremental releases are not unheard of I now need to establish what product launch/sales attributes should be applied to each sales release compared to the type of product launch that would typically come at the end of the development.  

Many thanks for your clear responses.