You're not alone, this is a common reaction to music notation by engineers; a lot of people have wondered the same thing, even here on HN. For example https://news.ycombinator.com/item?id=12528144 https://news.ycombinator.com/item?id=12085844
I see some great responses, but I wanted to add that you have to keep in mind that tons of people have actually tried to make a better system, and nobody has succeeded. That should give you enough pause to ask why and consider the possibility that the system we have is really good in a way that you haven't recognized yet.
I think the problem is that difficult to learn and bad are easily confused. It is difficult to learn.
Also keep in mind that music notation has undergone many iterations, and it represents developments over hundreds and hundreds of years and covers every instrument under the sun - the breadth of what it has done throughout history and what can do might be hard to see.