To cover the costs of a full-fledged fulfillment stack, you need to reach the critical mass of customers. If that is impossible due to limitations in initial market coverage, you can also reduce the cost of your stack.
Order Management Systems have an "Octopus nature", typically connecting to several northbound and southbound systems. These integrations are often costly due to complex interfaces.
Based on open source components, Pragmaxus AG designed an Order Manager tailored to a customer by size and capability. Having the knowledge of product and service modelling, as well of the key requirements for an order system, we could carve out the exact features needed for the customer situation.
It got the job well done at a fraction of the initially estimated costs.