Hi there, this is my first post, i am a front-end developer from spain working in a small company that sells real state appraisal-software, which is operating since early 90s.

The thing is, our top-selling software have 20 years old, written in old-windows-platform, and does not changed any since that. In my department we are leading the change from this old sw to cutting-edge data arquitecture and Web-application based platform (Angular, react, node, API-rest...).

Our customers has been working with our sw for a long without actually changes in the way of how they input their data inside our elderly-software.
They love to see ALL data they can see in their screen that fits (about 50 inputs) without navigation or sorted sections for their data. Inputs are so condensed, padding between them is actually non-existant.

As a front developer and ux, i cannot tolerate to put 50 input in a row, or make "excel-ish" forms with about 60 columns (putting Responsive design away...).

We made an approach with sections selectables from a sidebar, and inside sections there is "collapsables" containing input forms with about 14 inputs each. I mean, can you imagine how many inputs we have? Do the math. 5 sections, about 5 container collapsables inside (aprox), 14 inputs each container. About 300~ input that cannot being erased (i swear if i could, most of them will be going to be history).
Our customers, refuse to navigate between sections, they say: "we used to have all inputs all along my screen, i am not putting that away".

Have you face such a accomplishment? How do you make it? i've heard dev fellows that quit their job because of this huge-form-migrations. I am thinking about that.