A big reason I love reading novels is that things wrap up at the end. The bad guy is caught or killed or at the very least driven away from our hero and his/her loved ones. Everything is explained, and there is closure for those involved. They may have lost loved ones or several pints of blood or their sense of security, but we know they will recover and go on. Unless you're into noir, order is restored.
On the reality side, life is a mess. Crises don't come neatly one after the other, and certainly not in alphbetical order. Nothing is ever really solved, at least to the degree we would like. Good and bad things rise and fall with no regularity, and people don't get what they deserve, whatever that might be.
Authors try to write lifelike scenarios, of course. Sleuths have ongoing problems: alcoholic parents, dissatisfied spouses, rebellious children. They wrestle with demons from the past. They work with people who don't understand them or don't like them. They fall prey to temptations. They even fail. But somehow fiction wants to close a door, to say, "There. That's done." And that's something Life doesn't do. I guess that's why it's so satisfying to finish a well-written novel, because in some small corner of your world, good triumphs, and you can say along with the protagonist, "That ended up just the way I wanted it to."