I think that many have an unrealistic attitude when they get sober, it doesn't solve all of life's problems. Many of us still have that 'quick fix' mentality of when we used to drink/use, it's an ingrained impulse.
I suffer from some mental health diagnoses too. There can be good moments sober, but they are of a different quality from the experience of being high or intoxicated. However, they are also way more meaningful. And they don't wear off overnight and turn into nightmares the following day either.
If we didn't have our struggles or bad times, it would be harder perhaps to appreciate rewards and good things when they come to us. When I was addicted, every single thing that unpleasantly marred my experience had to be blocked or removed, but ultimately I realized that I had become entirely bankrupt inwardly from doing that.