Just anecdata, but as an engineer I think engineering is easy and design is hard.
For engineering you just have to follow logic, reasoning, good practices and have discipline. Also you can test your code to death to make sure everything is correct.
For design you have to have an artistic nature.
I believe that design should never be a creative process — when it is it means you are improvising — and that's simply disrespectful of the users. Well, you can have some sparks of creativeness (which usually is just an insight finally coming together from different datapoints now connected) but the process that brings you there is analytical, cynical, cold and methodical.
Explore the domain, document possibilities, group approaches and make comparisons.
To answer OP's question: the problem is usually time. If you spend 2 weeks developing a feature, why would you think 2 hours are enough to design it?
It would be like that Futurama episode where Fry writes a tv series episode script in hours and he's surprised that it lasts only 10 minutes.
The emotional result of perceiving the designed object, is still inside the realm of its function.
Maybe it’s because I just stepped away from a harrowing 5 hour troubleshooting session (which I’ll be continuing on Monday), but I just can’t bring myself to agree with your comment.
You (and too many other people) make it sound like engineering is akin to following steps in a cookbook.
I know what you mean, but I now read "artistic nature" as making subjective/arbitrary decisions that for some unknown reason a lot of people favor.
Though by the way I read d0m's comment, it seems like there's a fair amount of objectivity in graphic design as well. Lots of logic: If you need to design something, it's because you have a goal and you need to make every decision in that design further take you to that goal. Gotta pick a color for something? Your goal means influencing people? What's your target audience? Pick a color that's statistically known to elicit the emotions in your target audience that lead you to your goal.
There are parts of design where you just have to follow logic, reasoning, good practices and have discipline.
It's either art or work, the medium (code or visuals) is not important.
Ultimately, both code and aesthetics easy when building product. The hardest part is getting people to the product, signed up, onboarded, using, __and__ coming back for more...is very very hard.