Yes this was brought up multiple times early in development, but for the most part people then got used to simply deciding before taking the exit (assuming you're in a situation where you really have to look at your parts to make a decision).
It's a lot of work to redesign the evolution screen to accommodate this, and also complicates it beyond the current intended focus, and it's not just inventory, either--then people also start expecting even more functionality there, leading to a cascade of more related requests...
It's been on the list as a possible feature for years, but it's too low priority to probably ever reach that point. At best I could consider adding it to the patron voting list.