Do those RFPs come from the users or the buyers?

We had RAD tools like Access and we still have Excel. Even if they do lack some capability, you can do implement most of the core ideas of whatever features you’re trying to prototype. Actual coding is then to translate that to another platform and solve some accidental complexity.

Those core ideas are what’s valuable and they do not change often over the lifetime of a business. If the software has a good architecture, maintenance cost can be quite low.