Sure but the grandparent post is talking about moving to a low cost of living city for some company, and then some years later that company downsizing or closin

Sure but the grandparent post is talking about moving to a low cost of living city for some company, and then some years later that company downsizing or closing and laying people off, and then not having many other similar employment options available. So if you move, start a family because you can now afford it, and then lose your job 5 years later, you're going to be less mobile and also limited by job options.