I think simply put there was a lot I did not learn. In school you learn tradecraft. This is critical because without it you can’t be a designer. But what they don’t teach is the actual art of making a product. The tradecraft you learned makes up about 10-15% of the process. The rest of making a product is created in tandem with many other departments all working to gather on a timeline that will delivery the product on time to the customer. So what you need to learn are all the particular issues that might a rise.
Making a product to me feels like your a mountain climber. Coming out of school you had done some bouldering and some outdoor lead rope climbs but then you graduated. Now your first project will most likely be with an experience climber and you are going to do a know peak such as Mount Hood. As you gain experience you start to climb and lead your own climbs still on know peaks but harder and longer such as Denali. Then you reach a point were you start leading first accents. Now the pitfalls are less obvious so knowing the correct way to proceed to the top starts becoming more complicated. While doing first ascents there is no guide to reference all you can reference is the past climbs and what worked and did not work. This is the part that really applies to product creation for me. With years of experience you attain a good understand of the risk you are actually taking while designing a product. This allows you to design products that are innovative but also are manufacturable. Also you can smooth out a lot of the confusion and road blocks by understanding your impact on them and solving them before they become a problem.
The reason I like thinking about it this way is because like climbing a mountain there is a timeline that you have to adhere to. There is a start point and a end point which is how a product development calendar works. As you go through the process there are times were things start to go offer course how you adjust to this will determine the out come in both climbing and product creation. It is also and endurance sport which feels like the product process. The process is not immediate it takes a year or longer to create a product so you have to remain focused over a long period of time to get to the end of the process. How you did on all points will determine how the product is received or even if it is made.