By the standard of his own world, Ivan Ilyich had a good life; by the standard the novella ends up adopting, no, and this difference is what the book dramatizes.
By the standard of the world, he had everything: a rising career, an admired house, a family of decorous appearance, the game of vint with good partners. His colleagues liked him, and Ivan Ilyich himself, until he fell ill, believed that life was going as it should, light, pleasant, and decorous. In chapter IX, when the voice of the soul asks whether he has lived well, he reviews the joys and sees that they dissolve the closer they come to the present; only those of childhood endure. He concludes that he was going down the mountain while imagining he was going up.
In chapter XI comes the suspicion that the whole conscious life was not that, and in XII the certainty that the life was good is what holds him in the black bag. But the book does not condemn with simplicity: the narrator says his story was the simplest and most ordinary, which suggests that the error belongs to many people. And the last chapter leaves the door open: everything was not that, but one could still do that.
There are two readings. In one, the novella accuses a man who chose to copy the people above him. In the other, it describes a whole class, and Ivan Ilyich is one example among others. The text supports both.