To share my own experience, I always found design and development inherently connected. For me, it was always about creating the actual thing people use, not just creating a blueprint for it. But the reason I thought this way may have been some of my very early experiences in customizing video games in my teen years. For example, I built levels for Doom and 3D models for Quake. The tools available back then were made by fans, and extremely simple and buggy. So when you're building a level or a game character as a teenager with bare-bones tools, there is nobody to hand anything off to or explain anything to you. If you didn't figure out the whole process, you couldn't do what you wanted to do, it was that simple. And with that, I learned that the process from idea to final product is a long one, with lots of friction-points in between that can affect the result. So it just made sense to me that you needed to be intimately familiar with the whole process.