Depression doesn't need to paralyze you. You can be productive when depressed but it is often followed by a pattern of self destructive behavior.
I used to never understand why addicts would self destroy. They would get a job, finally get their lives together and then fuck it up.
Long term goals can feel pointless when you believe that you are insignificant and your life is meaningless. What's the point of improving my life by X factor if I'm gonna be dead anyway? What's the point of building this if it will be replaced by technology Y in Z years? What's the point of discovering this if eventually someone else will? What's the point if the Universe....
That type of thinking about the far future often results in defeatism.
In reality, you wake up the next day, having made no progress, your life is the same as yesterday, it may have gotten worse if you overindulged in your addiction and now you feel like utter shit.
A positive outlook on life and a focus on improving now, on evaluating each activity as a return on investment and building a better version of yourself feels more serene than admitting defeat.
I think comfort leads to stagnation. The best work I've done is when I was in survival mode and completely dissatisfied with my life. Once I reach "normalcy", procrastination and self indulgence kick in unless I see a point behind a long term goal.