An organization's IT systems and applications grow over time as needs change and more time and resources are available to do upgrades.
In house developers have a load of ongoing work from system users.
Progressive Development is a strategy to do what works now with the mindset that you will expand and replace it in the future.
When creating something for a client, you could scale down to the most minimal features and ship it, or you can prescribe a robust, fully featured system that will take longer to build and cost more.