If nobody does something there is a chance it doesn't work. The most problematic point to me seems to be point 3 'customer collaboration'. Does anybody know how to do that in real life? What does the sales team sell then? And more important how do you prevent feature creep from the customers side wanting more and more things during the process? To me I only see this working if you sell working time instead of a produ…
This is what we do at the consultancy I work at - billing is simply based on time & materials. We work from our customer's premises (when there isn't a global pandemic) and we have people from the customer integrated into our team, so customer collaboration is constant and continuous. Feature creep doesn't really happen, because all parties know what the budget is and how much our time costs.