How do researchers come up with these ideas?

Hi everyone. I have a question which is tickling my mind for a while now and I was hoping maybe you can help me. How do cv researchers come up with their ideas? I mean I have read over 100 cv papers (not much I know) but every single time I asked myself how? How is this justified? For example in object detection I've read Yolo v6, all I saw was that they experimented so many configuration with little to no insight, the same goes to most other papers, I mean yes I can understand why focal loss or arcface might help learning procedure but I cannot understand how traversing feature pyramid top to bottom or bottom to top or bidirectional or etc might help when there is no proper justification provides. Where is the intuition? I read a paper, the author stated that we fuse only top layers of FP together and bottom layers together and it works, why? How? I am really confused specially since started to work on my thesis. Which is about object detection.