Did you not read the earlier comments in this thread? That very point was already addressed.

The point the article is trying to make is that after selling the house, even after mortgage is settled, these homeowners have a lot of cash. Much more than their renter peers who are in the same position (houseless) and trying to find something they can afford.

The point above seems obvious when it's put like that, but it's still hard for people to grasp.

This is why the article argues that people who are in the privileged position of having huge equity in their house need to also consider what that does to their wealth class, even if they themselves don't believe it. A lot of home owners who have had a house for 10-15 years (and even more who paid off their house years ago) have no clue how much harder it has gotten for middle class income people to buy houses.