There are several factors that collide to make everything in software associated with health exponentially more difficult than in other areas. First, people's lives are actually on the line, the stakes are very high. Second, government regulation plays a significant role in how things can and cannot be done, this is a double edged sword in preventing some abuses but also making iteration and innovation more difficult.
The other most signifcant point is that there are often very large gaps in vision between different layers of a very large and complex human system. The needs of keeping the lights on and billing are often in direct tension to the needs of optimal care, this often manifests in software as a chimera that pleases no one.
One other tidbit I will add is well covered in my book's chapter "The incredible bandwidth of paper". When you actually sit in a room and see how fast and how complex the information recorded by a group of medical professionals with nothing but pen and paper form is, it is daunting to actually deliver that level of performance and reliability with any technology that exists today.